title: Error when building arm-elf-gcc
body: <p>I'm trying to build a arm-elf-gcc cross compiler.</p>
  
  <p>So firts I installed binutils 2.18 with the following configure options:</p>
  
  <pre><code>./configure --target=arm-elf --enable-interwork --enable-multilib
  </code></pre>
  
  <p>This seems to work fine.</p>
  
  <p>next I installed gmp, mpfr and libmpc </p>
  
  <p>so now to the gcc itself.</p>
  
  <p>//edit - removed previous error and updated with the current one (I tried to build everything separately)</p>
  
  <p>First I install a bootstrap gcc with these configure options:</p>
  
  <pre><code>--target=arm-elf --disable-libssp --with-newlib --without-headers --with-gnu-as --with-gnu-ld
  </code></pre>
  
  <p>And afterwards I try to build newlib 1.17.0 with it</p>
  
  <pre><code>--target=arm-elf --disable-werror --disable-newlib-supplied-syscalls --disable-nls --with-gnu-as --with-gnu-ld
  </code></pre>
  
  <p>But this still results in the same error. Maybe newlib tries to build for x86 architecture with the apple gcc (I'm running these things all on OS X) which maybe doesn't understand these parameters?</p>
  
  <pre><code>    cc1: error: unrecognized command line option "-msse4"
  ../../../../../../newlib/libc/argz/dummy.c:1: error: bad value (core2) for -march= switch
  cc1: error: unrecognized command line option "-msse4"
  FATAL:/usr/bin/../libexec/gcc/darwin/x86_64/as: I don't understand 'm' flag!
  ../../../../../../newlib/libc/argz/argz_add.c:1: error: bad value (core2) for -march= switch
  cc1: error: unrecognized command line option "-msse4"
  ../../../../../../newlib/libc/argz/argz_add_sep.c:1: error: bad value (core2) for -march= switch
  cc1: error: unrecognized command line option "-msse4"
  make[8]: *** [lib_a-argz_add.o] Error 1
  make[8]: *** Waiting for unfinished jobs....
  ../../../../../../newlib/libc/argz/argz_append.c:1: error: bad value (core2) for -march= switch
  FATAL:/usr/bin/../libexec/gcc/darwin/x86_64/as: I don't understand 'm' flag!
  cc1: error: unrecognized command line option "-msse4"
  ../../../../../../newlib/libc/argz/argz_create.c:1: error: bad value (core2) for -march= switch
  cc1: error: unrecognized command line option "-msse4"
  ../../../../../../newlib/libc/argz/argz_count.c:1: error: bad value (core2) for -march= switch
  FATAL:/usr/bin/../libexec/gcc/darwin/x86_64/as: I don't understand 'm' flag!
  cc1: error: unrecognized command line option "-msse4"
  ../../../../../../newlib/libc/argz/argz_delete.c:1: error: bad value (core2) for -march= switch
  make[8]: *** [lib_a-dummy.o] Error 1
  make[8]: *** [lib_a-argz_create.o] Error 1
  FATAL:/usr/bin/../libexec/gcc/darwin/x86_64/as: I don't understand 'm' flag!
  FATAL:/usr/bin/../libexec/gcc/darwin/x86_64/as: I don't understand 'm' flag!
  FATAL:/usr/bin/../libexec/gcc/darwin/x86_64/as: I don't understand 'm' flag!
  make[8]: *** [lib_a-argz_add_sep.o] Error 1
  make[8]: *** [lib_a-argz_delete.o] Error 1
  FATAL:/usr/bin/../libexec/gcc/darwin/x86_64/as: I don't understand 'm' flag!
  make[8]: *** [lib_a-argz_count.o] Error 1
  make[8]: *** [lib_a-argz_append.o] Error 1
  FATAL:/usr/bin/../libexec/gcc/darwin/x86_64/as: I don't understand 'm' flag!
  cc1: error: unrecognized command line option "-msse4"
  ../../../../../../newlib/libc/argz/argz_create_sep.c:1: error: bad value (core2) for -march= switch
  make[8]: *** [lib_a-argz_create_sep.o] Error 1
  make[7]: *** [all-recursive] Error 1
  make[6]: *** [all-recursive] Error 1
  make[5]: *** [all] Error 2
  make[4]: *** [multi-do] Error 1
  make[3]: *** [all-multi] Error 2
  make[2]: *** [all] Error 2
  make[1]: *** [all-target-newlib] Error 2
  make: *** [all] Error 2
  </code></pre>