[Driver] Support -muclibc / -mglibc command line options for a couple
of MIPS toolchains.

The uCLibc implemented for multiple architectures. A couple of MIPS toolchains
contains both uCLibc and glibc implementation so these options allow to select
used C library.

Initially -muclibc / -mglibc (as well as -mbionic) have been implemented in gcc
for various architectures so they are not MIPS specific.

llvm-svn: 215552
diff --git a/clang/lib/Driver/Tools.h b/clang/lib/Driver/Tools.h
index 1b31411..b248caa 100644
--- a/clang/lib/Driver/Tools.h
+++ b/clang/lib/Driver/Tools.h
@@ -223,6 +223,7 @@
                         const llvm::Triple &Triple, StringRef &CPUName,
                         StringRef &ABIName);
   bool hasMipsAbiArg(const llvm::opt::ArgList &Args, const char *Value);
+  bool isUCLibc(const llvm::opt::ArgList &Args);
   bool isNaN2008(const llvm::opt::ArgList &Args, const llvm::Triple &Triple);
   bool isFPXXDefault(const llvm::Triple &Triple, StringRef CPUName,
                      StringRef ABIName);