title: Fedora 21 with clang, without gcc
body: <p>Can you (reasonably) get Fedora 21 to where it only has llvm/clang/libc++/libc++abi?  (I found some things suggesting no, but they were all about 3 years old, and llvm/clang has come a long way since then.)</p>
  
  <p>With a fresh install, I tried</p>
  
  <pre><code>yum install gcc gcc-c++
  (downloaded, built, installed llvm/cfe(clang)/compiler-rt/libcxx/libcxxabi from svn)
  yum remove gcc gcc-c++
  added to /etc/profile: export CC=/usr/local/bin/clang \ export CXX=/usr/local/bin/clang++
  (in case of hard wiring)
  ln -s /usr/local/bin/clang /usr/local/bin/gcc
  ln -s /usr/local/bin/clang /usr/local/bin/cc
  ln -s /usr/local/bin/clang++ /usr/local/bin/g++
  ln -s /usr/local/bin/clang++ /usr/local/bin/c++
  ldconfig
  </code></pre>
  
  <p>I was all happy, then went to build something, and I got:</p>
  
  <pre><code>ld: cannot find crtbegin.o
  ld: cannot find -lgcc
  ld: cannot find -lgcc_s
  </code></pre>
  
  <p>clang -v includes</p>
  
  <pre><code>Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/4.9.2
  </code></pre>
  
  <p>ldconfig &amp;&amp; ldconfig -p | grep libgcc does show</p>
  
  <pre><code>libgcc_s.so.1 (libc6,x86-64) =&gt; /lib64/libgcc_s.so.1
  </code></pre>
  
  <p>And /lib64 is a symlink to /usr/lib64.  And, /usr/lib64/libgcc_s.so.1 is a symlink to /usr/lib64/libgcc_s-4.9.2-20150212.so.1, which exists as a real file (92816 bytes.)</p>
  
  <p>So, I don't get what ld's problem is on -lgcc_s.  crtbegin is nowhere to be found, and gcc (no _s) is nowhere to be found.</p>
  
  <p>yum install libgcc says it's already installed and latest version, nothing to do.</p>
  
  <p>Since I have an installed clang source build, can I re-build clang, this time using clang rather than gcc, to get rid of the dependency?  (Maybe then the "candidate GCC installation" bit goes away.)</p>
  
  <p>Can I force -stdlib=c++ and -lc++abi to be default, or at least have libc++ and libc++abi installed without gcc?</p>