Honor -Wl,--no-fatal-warnings, even in strict mode. (#22255)

Fixes: #22253

Author: sbc100

test/test_other.py

@@ -12154,7 +12154,11 @@ def test_signature_mismatch(self):
     stderr = self.run_process([EMCC, 'a.c', 'b.c'], stderr=PIPE).stderr
     self.assertContained('function signature mismatch: foo', stderr)
     self.expect_fail([EMCC, '-Wl,--fatal-warnings', 'a.c', 'b.c'])
+    # STRICT mode implies fatal warnings
     self.expect_fail([EMCC, '-sSTRICT', 'a.c', 'b.c'])
+    # Unless `--no-fatal-warnings` is explictly passed
+    stderr = self.run_process([EMCC, '-sSTRICT', '-Wl,--no-fatal-warnings', 'a.c', 'b.c'], stderr=PIPE).stderr
+    self.assertContained('function signature mismatch: foo', stderr)
 
   # Verifies that warning messages that Closure outputs are recorded to console
   def test_closure_warnings(self):

tools/building.py

@@ -264,7 +264,7 @@ def link_lld(args, target, external_symbols=None):
     args.insert(0, '--whole-archive')
     args.append('--no-whole-archive')
 
-  if settings.STRICT:
+  if settings.STRICT and '--no-fatal-warnings' not in args:
     args.append('--fatal-warnings')
 
   if any(a in args for a in ('--strip-all', '-s')):