Fix "basename" and "__cpu_mask" definitions for musl

Upstream PR: https://github.com/ROCm/clr/pull/83
--- a/rocclr/os/os.hpp
+++ b/rocclr/os/os.hpp
@@ -29,6 +29,7 @@
 
 #if defined(__linux__)
 #include <sched.h>
+#include <libgen.h>
 #endif
 
 #ifdef _WIN32
@@ -377,6 +378,10 @@ ALWAYSINLINE address Os::currentStackPtr() {
 
 #if defined(__linux__)
 
+#ifndef __GLIBC__
+typedef unsigned long int __cpu_mask;
+#endif
+
 inline void Os::ThreadAffinityMask::init() { CPU_ZERO(&mask_); }
 
 inline void Os::ThreadAffinityMask::set(uint cpu) { CPU_SET(cpu, &mask_); }