LLVM code generator emits the ".file filename" directive for ELF
backends. Value of the "filename" is set as the LLVM module identifier.
Due to a LLVM MC bug[1], LLVM crashes if the module identifer is same as
other symbols such as a function name in the module.
This patch adds a ".rc" suffix (means crates) to LLVM module identifier
to workaround the bug.
Fixes issue #1251.
1. http://llvm.org/bugs/show_bug.cgi?id=11479