Diagnostics from modules do not have a `main-file` listed. Tweak
`clang-parse-diagnostics-file` to patch this up. Previously, the call
to `os.path.basename` would crash.
Radar-Id: rdar://problem/
59000292
for file_diags in diags:
file = file_diags.get('main-file')
+ # Diagnostics from modules don't have a main-file listed.
+ if not file:
+ file = '<module-includes>'
+
# Ignore diagnostics for 'conftest.c', which is the file autoconf uses
# for its tests (which frequently will have warnings).
if os.path.basename(file) == 'conftest.c':