[sanitizer] Don't compile GetPathAssumingFileIsRelativeToExec on Fuchsia

[phosek]

Summary

This avoids the unused function warning during compilation.

[vitalybuka]

compiler-rt/lib/sanitizer_common/sanitizer_suppressions.cc

55

Can you extract this into a function so we have no #if !SANITIZER_FUCHSIA here
and just single if with different definitions of the function?

[vitalybuka]

LGTM either way

compiler-rt/lib/sanitizer_common/sanitizer_suppressions.cc

SuppressionContext::SuppressionContext(const char *suppression_types[],
                                        int suppression_types_num)
     : suppression_types_(suppression_types),
       suppression_types_num_(suppression_types_num),
       can_parse_(true) {
   CHECK_LE(suppression_types_num_, kMaxSuppressionTypes);
   internal_memset(has_suppression_type_, 0, suppression_types_num_);
 }
 
+#if !SANITIZER_FUCHSIA
 static bool GetPathAssumingFileIsRelativeToExec(const char *file_path,
                                                 /*out*/char *new_file_path,
                                                 uptr new_file_path_size) {
   InternalScopedString exec(kMaxPathLength);
   if (ReadBinaryNameCached(exec.data(), exec.size())) {
     const char *file_name_pos = StripModuleName(exec.data());
     uptr path_to_exec_len = file_name_pos - exec.data();
     internal_strncat(new_file_path, exec.data(),
                      Min(path_to_exec_len, new_file_path_size - 1));
     internal_strncat(new_file_path, file_path,
                      new_file_path_size - internal_strlen(new_file_path) - 1);
     return true;
   }
   return false;
 }
+#endif
 
 void SuppressionContext::ParseFromFile(const char *filename) {
   if (filename[0] == '\0')
     return;
 
 #if !SANITIZER_FUCHSIA
   // If we cannot find the file, check if its location is relative to
   // the location of the executable.
   InternalScopedString new_file_path(kMaxPathLength);
   if (!FileExists(filename) && !IsAbsolutePath(filename) &&
       GetPathAssumingFileIsRelativeToExec(filename, new_file_path.data(),
                                           new_file_path.size())) {
     filename = new_file_path.data();
   }