__inline is a vendor specific spelling for inline. clang and gcc treat it the
same as inline, and is available in MSVC 2013 which does not implement C99
(VS2015 supports the inline keyword though). This will allow us to build the
builtins using MSVC.
llvm-svn: 249953
clang does not like the definition of builtins. In order to work around this,
we use a SUN CC to redefine the generated name. However, this requires that we
account for the user label prefix. Rather than hard coding that into the file,
rely on the compiler to tell us the information and use the preprocessor to
generate the name as we do in the assembly routines. NFC.
llvm-svn: 224597
