Issue title: Linking fails attempting to run cc (fork returns -1)
 Issue body: Hi,

I am getting this when trying to compile Rust 0.6 (tarball downloaded via the website):

```
progval@Andromede:~/src/rust-0.6$ RUST_LOG=rustc=1,38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5rt38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ktrace make
cfg: build triple x86_64-unknown-linux-gnu
cfg: host triples x86_64-unknown-linux-gnu
cfg: target triples x86_64-unknown-linux-gnu
cfg: host for x86_64-unknown-linux-gnu is x86_64
cfg: os for x86_64-unknown-linux-gnu is unknown-linux-gnu
cfg: using gcc
cfg: no pandoc found, omitting doc/rust.pdf
cfg: no llnextgen found, omitting grammar-verification
cfg: no pandoc found, omitting library doc build
compile_and_link: x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so
rust: task failed at 'explicit failure', /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/libcore/run.rs:343
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4f)[0x2b57134fc52f]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(+0x299f1)[0x2b571350c9f1]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(upcall_fail+0x1c6)[0x2b57134fecb6]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x1059ab)[0x2b57101f39ab]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x105952)[0x2b57101f3952]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(_ZN3sys12begin_unwind16_701b8ec61f97ead3_06E+0x71)[0x2b571013b441]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(_ZN3run14program_output16_3596fc6920d4f353_06E+0x2872)[0x2b57101edaa2]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x14e214)[0x2b571023c214]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN4back4link11link_binary17_483345abdae712883_06E+0x3a9d)[0x2b57118ccbad]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x5db835)[0x2b5711695835]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver12compile_rest16_87c0f340aa21a393_06E+0x40e2)[0x2b57119332b2]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b9e84)[0x2b5711973e84]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver12compile_upto17_84743710faafb0af3_06E+0x108)[0x2b5711935738]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b9e84)[0x2b5711973e84]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver13compile_input15_a6b0fe22676e6b3_06E+0xca)[0x2b5711935b7a]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN12run_compiler16_9de519bbeb758373_06E+0x20aa)[0x2b571196531a]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b7951)[0x2b5711971951]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b417c)[0x2b571196e17c]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b9e84)[0x2b5711973e84]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0xce38e)[0x2b57101bc38e]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x14e214)[0x2b571023c214]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x2b57134fd534]
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug
note: try running with RUST_LOG=rustc=1,38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5rt38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ktrace to get further details and report the results to github.com/mozilla/rust/issues
rust: task failed at 'explicit failure', /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/librustc/rustc.rc:357
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4f)[0x2b57134fc52f]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(+0x299f1)[0x2b571350c9f1]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(upcall_fail+0x1c6)[0x2b57134fecb6]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x1059ab)[0x2b57101f39ab]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x105952)[0x2b57101f3952]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(_ZN3sys12begin_unwind16_701b8ec61f97ead3_06E+0x71)[0x2b571013b441]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x14e214)[0x2b571023c214]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN7monitor17_ab3b5d4d4b9efdb63_06E+0x1577)[0x2b5711967947]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b9e84)[0x2b5711973e84]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN4main16_706f4ee7413ae583_06E+0x7e)[0x2b5711973a9e]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x2b57134fd534]
rust: domain main @0xe6f3c0 root task failed
make: *** [x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so] Erreur 101
```

I use Debian Sid (amd64).

Regards,
Valentin

 Comments: 
 Comment 0: I just deleted everything and compiled it again. Now it makes it to stage2, and then fails with the same error.

 Comment 1: I can't compile to. I'm on debian squeeze.
The output is the same.

 Comment 2: It would probably help diagnosis if you followed the error's advice
`note: try running with RUST_LOG=rustc=1,38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5rt38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ktrace to get further details and report the results to github.com/mozilla/rust/issues`, and posted that output.

 Comment 3: More helpful would be running rustc under gdb and breaking on rust_task_fail. The backtrace from there is must more useful.

 Comment 4: @crazymykl That's what I did. See the first line of the block.

@jdm How?

 Comment 5: Run make with VERBOSE=1 to see the actual command that's failing. Run `gdb --args ...` where ... is the command you just found, and use `break rust_task_fail` followed by `run`. When the breakpoint is hit, use `bt` and paste the output.

 Comment 6: @ProgVal mea culpa. At least some attention was drawn to the bug by my mistake.

 Comment 7: @jdm 

```
progval@Andromede:~/src/rust-0.6$ VERBOSE=1 RUST_LOG=rustc=1,38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5rt38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ktrace make
cfg: build triple x86_64-unknown-linux-gnu
cfg: host triples x86_64-unknown-linux-gnu
cfg: target triples x86_64-unknown-linux-gnu
cfg: host for x86_64-unknown-linux-gnu is x86_64
cfg: os for x86_64-unknown-linux-gnu is unknown-linux-gnu
cfg: using gcc
cfg: no pandoc found, omitting doc/rust.pdf
cfg: no llnextgen found, omitting grammar-verification
cfg: no pandoc found, omitting library doc build
x86_64-unknown-linux-gnu/stage0/bin/rustc --cfg stage0  -O  --target=x86_64-unknown-linux-gnu  -o x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so /home/progval/src/rust-0.6/src/librustc/rustc.rc && touch x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so
^Cmake: *** [x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so] Interrompre

progval@Andromede:~/src/rust-0.6$ gdb --args x86_64-unknown-linux-gnu/stage0/bin/rustc --cfg stage0  -O  --target=x86_64-unknown-linux-gnu  -o x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so /home/progval/src/rust-0.6/src/librustc/rustc.rc
GNU gdb (GDB) 7.4.1-debian
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/rustc...(no debugging symbols found)...done.
(gdb) break rust_task_fail
Function "rust_task_fail" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (rust_task_fail) pending.
(gdb) run
Starting program: /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/rustc --cfg stage0 -O --target=x86_64-unknown-linux-gnu -o x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so /home/progval/src/rust-0.6/src/librustc/rustc.rc
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff7ff6700 (LWP 22059)]
[New Thread 0x7ffff7fdd700 (LWP 22063)]
[New Thread 0x7ffff7fd8700 (LWP 22064)]
[Switching to Thread 0x7ffff7fd8700 (LWP 22064)]

Breakpoint 1, rust_task_fail (task=0x6106f0, expr=0x26dd5c20 "explicit failure", file=0x20f0ba10 "/home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/libcore/run.rs", line=343)
    at /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/rt/rust_task.cpp:85
85  /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/rt/rust_task.cpp: Aucun fichier ou dossier de ce type.
```

("Aucun fichier ou dossier de ce type" means "No such file or directory")

 Comment 8: What about the full backtrace output from `bt`?

 Comment 9: Oops, sorry.

```
#0  rust_task_fail (task=0x6106f0, expr=0x26dd5c20 "explicit failure", file=0x20f0ba10 "/home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/libcore/run.rs", line=343)
    at /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/rt/rust_task.cpp:85
#1  0x00007ffff47b89f1 in __morestack () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so
#2  0x00007ffff47aacb6 in call_on_c_stack (fn_ptr=0x7ffff47a9dc0, args=0x6333f0, this=0x6106f0) at /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/rt/rust_task.h:470
#3  call_upcall_on_c_stack (fn_ptr=0x7ffff47a9dc0, args=0x6333f0, task=<optimized out>) at /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/rt/rust_upcall.cpp:45
#4  upcall_fail (expr=<optimized out>, file=0x20f0ba10 "/home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/libcore/run.rs", line=343)
    at /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/rt/rust_upcall.cpp:128
#5  0x00007ffff79d19ab in sys38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5gin_unwind_38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_f79ba45ac6338d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_06 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so
#6  0x00007ffff79d1952 in sys38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5gin_unwin38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5anon38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5non38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5xpr_fn_14663 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so
#7  0x00007ffff7919441 in sys38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5gin_unwin38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_701b8ec61f938d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_06 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so
#8  0x00007ffff79cbaa2 in run38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5program_output38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_3596fc6920d38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_06 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so
#9  0x00007ffff7a1a214 in __morestack () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so
#10 0x00007ffff68e0bad in back38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5link38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5link_binary38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_483345abdae738d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_06 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#11 0x00007ffff66a9835 in util38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ommon38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5time_538d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_71a86f54b88338d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_06 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#12 0x00007ffff69472b2 in driver38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5river38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ompile_rest38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_87c0f340aa238d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_06 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#13 0x00007ffff6987e84 in __morestack () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#14 0x00007ffff6949738 in driver38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5river38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ompile_upto38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_84743710faaf38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_06 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#15 0x00007ffff6987e84 in __morestack () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#16 0x00007ffff6949b7a in driver38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5river38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ompile_input38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_a6b0fe226738d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_06 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#17 0x00007ffff697931a in run_compiler38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_9de519bbeb738d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5_06 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#18 0x00007ffff6985951 in monitor38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5non38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5xpr_fn_81957 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#19 0x00007ffff698217c in task38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5__extensions__38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5try_838d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5anon38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5xpr_fn_81741 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#20 0x00007ffff6987e84 in __morestack () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so
#21 0x00007ffff799a38e in task38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5spawn38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5spawn_raw38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5make_child_wrapper38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5non38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5xpr_fn_12071 () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so
#22 0x00007ffff7a1a214 in __morestack () from /home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so
#23 0x00007ffff47a9534 in task_start_wrapper (a=<optimized out>) at /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/rt/rust_task.cpp:162
#24 0x0000000000000000 in ?? ()
```

 Comment 10: You apparently lack a `cc` binary.

 Comment 11: What do you mean? I have `cc` in my PATH.

And stages 0 and 1 worked once. (I tried to run "make clean" and then "make", but stage 0 fails again)

 Comment 12: What's the output of running make with `RUST_LOG=rust38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5back38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5link`?

 Comment 13: RUST_LOG=rust38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5back38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5link make >journal.txt 2>&1
less journal.txt 

cfg: build triple x86_64-unknown-linux-gnu
cfg: host triples x86_64-unknown-linux-gnu
cfg: target triples x86_64-unknown-linux-gnu
cfg: host for x86_64-unknown-linux-gnu is x86_64
cfg: os for x86_64-unknown-linux-gnu is unknown-linux-gnu
cfg: using gcc
cfg: no pandoc found, omitting doc/rust.pdf
cfg: no llnextgen found, omitting grammar-verification
cfg: no pandoc found, omitting library doc build
compile_and_link: x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so
rust: ~"link_meta.name:  rustc"
rust: ~"long_libname: librustc-c84825241471686d-0.6.so"
rust: ~"out_filename: x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so"
rust: ~"dirname(out_filename): x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib"
rust: ~"output: x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc-c84825241471686d-0.6.so"
rust: ~"cc link args: -L/home/claire/download/rust-0.6/x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib -m64 -o x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc-c84825241471686d-0.6.so x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.o -L/home/claire/download/rust-0.6/x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib -lcore-c3ca5d77d81b46c1-0.6 -L/home/claire/download/rust-0.6/x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib -lstd-4782a756585a81-0.6 -L/home/claire/download/rust-0.6/x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib -lsyntax-84efebcb12c867a2-0.6 -Lrustllvm -lrustllvm -lrustrt -lrt -lpthread -shared -lrt -ldl -lm -lmorestack -lrustrt -Wl,-rpath,$ORIGIN/. -Wl,-rpath,/home/claire/download/rust-0.6/x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib -Wl,-rpath,/usr/local/lib/rustc/x86_64-unknown-linux-gnu/lib"
rust: task failed at 'explicit failure', /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/libcore/run.rs:343
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug
note: try running with RUST_LOG=rustc=1,38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5rt38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ktrace to get further details and report the results to github.com/mozilla/rust/issues
rust: task failed at 'explicit failure', /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/librustc/rustc.rc:357
rust: domain main @0x9f93c0 root task failed
make: **\* [x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so] Erreur 101
~

 Comment 14: ```
progval@Andromede:~/src/rust-0.6$ RUST_LOG=rust38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5back38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5link VERBOSE=1 RUST_LOG=rustc=1,38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5rt38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ktrace make
cfg: build triple x86_64-unknown-linux-gnu
cfg: host triples x86_64-unknown-linux-gnu
cfg: target triples x86_64-unknown-linux-gnu
cfg: host for x86_64-unknown-linux-gnu is x86_64
cfg: os for x86_64-unknown-linux-gnu is unknown-linux-gnu
cfg: using gcc
cfg: no pandoc found, omitting doc/rust.pdf
cfg: no llnextgen found, omitting grammar-verification
cfg: no pandoc found, omitting library doc build
x86_64-unknown-linux-gnu/stage0/bin/rustc --cfg stage0  -O  --target=x86_64-unknown-linux-gnu  -o x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so /home/progval/src/rust-0.6/src/librustc/rustc.rc && touch x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so
rust: task failed at 'explicit failure', /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/libcore/run.rs:343
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4f)[0x2b277d8d452f]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(+0x299f1)[0x2b277d8e49f1]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(upcall_fail+0x1c6)[0x2b277d8d6cb6]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x1059ab)[0x2b277a5cb9ab]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x105952)[0x2b277a5cb952]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(_ZN3sys12begin_unwind16_701b8ec61f97ead3_06E+0x71)[0x2b277a513441]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(_ZN3run14program_output16_3596fc6920d4f353_06E+0x2872)[0x2b277a5c5aa2]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x14e214)[0x2b277a614214]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN4back4link11link_binary17_483345abdae712883_06E+0x3a9d)[0x2b277bca4bad]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x5db835)[0x2b277ba6d835]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver12compile_rest16_87c0f340aa21a393_06E+0x40e2)[0x2b277bd0b2b2]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b9e84)[0x2b277bd4be84]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver12compile_upto17_84743710faafb0af3_06E+0x108)[0x2b277bd0d738]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b9e84)[0x2b277bd4be84]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver13compile_input15_a6b0fe22676e6b3_06E+0xca)[0x2b277bd0db7a]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN12run_compiler16_9de519bbeb758373_06E+0x20aa)[0x2b277bd3d31a]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b7951)[0x2b277bd49951]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b417c)[0x2b277bd4617c]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b9e84)[0x2b277bd4be84]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0xce38e)[0x2b277a59438e]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x14e214)[0x2b277a614214]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x2b277d8d5534]
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug
note: try running with RUST_LOG=rustc=1,38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5rt38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5ktrace to get further details and report the results to github.com/mozilla/rust/issues
rust: task failed at 'explicit failure', /home/rustbuild/src/rust-buildbot/slave/snap3-linux/build/src/librustc/rustc.rc:357
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4f)[0x2b277d8d452f]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(+0x299f1)[0x2b277d8e49f1]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(upcall_fail+0x1c6)[0x2b277d8d6cb6]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x1059ab)[0x2b277a5cb9ab]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x105952)[0x2b277a5cb952]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(_ZN3sys12begin_unwind16_701b8ec61f97ead3_06E+0x71)[0x2b277a513441]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x14e214)[0x2b277a614214]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN7monitor17_ab3b5d4d4b9efdb63_06E+0x1577)[0x2b277bd3f947]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8b9e84)[0x2b277bd4be84]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN4main16_706f4ee7413ae583_06E+0x7e)[0x2b277bd4ba9e]
/home/progval/src/rust-0.6/x86_64-unknown-linux-gnu/stage0/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x2b277d8d5534]
rust: domain main @0x13bb3c0 root task failed
make: *** [x86_64-unknown-linux-gnu/stage0/lib/rustc/x86_64-unknown-linux-gnu/lib/librustc.so] Erreur 101
```

 Comment 15: I've updated the title to reflect the error your logs show. I'm mystified why run38d1:d2b4:3d06:83e8:96a5:8c2:893d:aba5program_output would report that `cc` can't be found if it's in your path; it just ends up using `fork` and `execvp`.

 Comment 16: Although, reading the source of rust_run_program.cpp, apparently the `fork` call is failing.

 Comment 17: Could that be because it cannot allocate enough memory to the fork? The process uses about 35% of my RAM when it crashes (I have no SWAP).

EDIT: That would explain why stages 0 and 1 worked once.

 Comment 18: I closed Firefox (ie. what consumes the more memory ;) ) and stage0
just passed.

 Comment 19: and... it worked!

I'm not closing this issue as requiring so much memory (more than 2GB) is still a problem, isn't it?

 Comment 20: Alas, rustc does use a lot of memory. I think there's no other bug here; reopen if I'm confused.

{'source': 'GithubIssues', 'repo_name_with_owner': 'rust-lang/rust', 'issue_id': 12899108, 'repo_stars': 73938.0}