[compiler-rt][profile][AIX] pass extra link opts for test

[daltenty]

Summary

The AIX linker doesn't export any symbols by default, so an export list is usually used. Since clang doesn't have the tools to auto-generate an export list yet, just pass the linker an extra opt to tell it to export everything, which generally not recommended for real shared libs, is fine for the purpose of this test.

compiler-rt/test/profile/Posix/instrprof-get-filename-merge-mode.c

 // Test __llvm_profile_get_filename when the on-line merging mode is enabled.
 //
-// RUN: %clang_pgogen -fPIC -shared -o %t.dso %p/../Inputs/instrprof-get-filename-dso.c
+// RUN: %clang_pgogen -fPIC -shared %shared_linker_xopts -o %t.dso %p/../Inputs/instrprof-get-filename-dso.c
 // RUN: %clang_pgogen -o %t %s %t.dso
 // RUN: env LLVM_PROFILE_FILE="%t-%m.profraw" %run %t
 
 #include <string.h>
 
 const char *__llvm_profile_get_filename(void);
 extern const char *get_filename_from_DSO(void);
 
 int main(int argc, const char *argv[]) {
   const char *filename1 = __llvm_profile_get_filename();
   const char *filename2 = get_filename_from_DSO();
 
   // Exit with code 1 if the two filenames are the same.
   return strcmp(filename1, filename2) == 0;
 }

compiler-rt/test/profile/Posix/lit.local.cfg.py

 def getRoot(config):
   if not config.parent:
     return config
   return getRoot(config.parent)
 
 root = getRoot(config)
 
 if root.host_os in ['Windows']:
   config.unsupported = True
+
+# AIX usually usually makes use of an explicit export list when linking a shared
+# object, but for the purposes of these tests just export all symbols.
+if root.host_os in ['AIX']:
+  config.substitutions.append(('%shared_linker_xopts', '-Wl,-bexpfull'))
+else:
+  config.substitutions.append(('%shared_linker_xopts', ''))