Unify the name of compiler-rt builtins library on Linux.

Call it "libclang_rt.builtins-<arch>.a" to be consistent
with sanitizers/profile libraries naming. Modify Makefile
and CMake build systems and Clang driver accordingly.

Fixes PR19822.

llvm-svn: 209474
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index e51cb1b..3fe552d 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1891,14 +1891,15 @@
   return Res;
 }
 
-// This adds the static libclang_rt.arch.a directly to the command line
+// This adds the static libclang_rt.builtins-arch.a directly to the command line
 // FIXME: Make sure we can also emit shared objects if they're requested
 // and available, check for possible errors, etc.
 static void addClangRTLinux(
     const ToolChain &TC, const ArgList &Args, ArgStringList &CmdArgs) {
   SmallString<128> LibClangRT = getCompilerRTLibDir(TC);
-  llvm::sys::path::append(LibClangRT,
-      Twine("libclang_rt.") + getArchNameForCompilerRTLib(TC) + ".a");
+  llvm::sys::path::append(LibClangRT, Twine("libclang_rt.builtins-") +
+                                          getArchNameForCompilerRTLib(TC) +
+                                          ".a");
 
   CmdArgs.push_back(Args.MakeArgString(LibClangRT));
   CmdArgs.push_back("-lgcc_s");