llvm: fix building with musl libc

[martell]

Summary

musl uses #define to map some 64 type functions for backwards compatibility.
this breaks building LLVM which assumes GLIBC in a lot of places.

There is no MUSL macro so this is the best way to detect it currently.
One would presume the #undef's should be safe without a guard.
This is just a precaution. Suggested improvements welcome :)

[krytarowski]

What are the exact build failures? This patch looks wrong.

[efriedma]

I thought we fixed this in r292848; is this still an issue on trunk?

[martell]

In D34943#798192, @krytarowski wrote:

What are the exact build failures? This patch looks wrong.

Hmm, after updating to HEAD it seems to pass, this was an issue for the 4.0 release but has since been fixed.
Going to abandon this.
Sorry for the noise.

[martell]

@efriedma thanks for clarifying where it was fixed

include/llvm/Analysis/TargetLibraryInfo.h

 #include "llvm/IR/PassManager.h"
 #include "llvm/Pass.h"
 
+#if defined(__linux__) and !defined(__GLIBC__) and !defined(__ANDROID__)
+#undef fopen64
+#undef fseeko64
+#undef fstat64
+#undef fstatvfs64
+#undef ftello64
+#undef lstat64
+#undef stat64
+#undef tmpfile64
+#undef F_GETLK64
+#undef F_SETLK64
+#undef F_SETLKW64
+#undef flock64
+#undef open64
+#undef openat64
+#undef creat64
+#undef lockf64
+#undef posix_fadvise64
+#undef posix_fallocate64
+#undef off64_t
+#endif
+
 namespace llvm {
 template <typename T> class ArrayRef;