Add profiling support to AIX

AIX ld needs special option to merge objects with profiling. Also,
profiler_builtins should include builtins for AIX from compiler-rt.

Author: ecnelises

profiler_builtins/build.rs

@@ -26,6 +26,7 @@ fn main() {
         "InstrProfilingMerge.c",
         "InstrProfilingMergeFile.c",
         "InstrProfilingNameVar.c",
+        "InstrProfilingPlatformAIX.c",
         "InstrProfilingPlatformDarwin.c",
         "InstrProfilingPlatformFuchsia.c",
         "InstrProfilingPlatformLinux.c",