Check behavior with GNUC allowed

tests/conftest.py

@@ -48,7 +48,7 @@ def module_from_code(name, python_code):
 
 COUNTER = 0
 
-def generate(header=None, args=[], lang="py", cpp=MAIN_CPP):
+def generate(header=None, args=[], lang="py", cpp=MAIN_CPP, allow_gnuc=True):
 
     # Windows notes:
     # - Avoid stdlib tempfiles, they're not usable by anyone except the direct creator, otherwise you'll get permission errors.
@@ -66,6 +66,7 @@ def generate(header=None, args=[], lang="py", cpp=MAIN_CPP):
         cmdargs += ["-i", tmp_in]
 
     if cpp: cmdargs += ["--cpp", cpp]
+    if allow_gnuc: cmdargs += ["-X", "__GNUC__"]
     cmdargs += ["--output-language", lang] + args
 
     try:

tests/testsuite.py

@@ -930,12 +930,12 @@ def test_ordered_passthrough(self):
     @requires_gcc
     def test_default_undef(self):
         # this actually works because the def/undef are taken over into the output, so we won't get a "no target members" exception.
-        m = generate("", ["--symbol-rules", "yes=__GNUC__"], cpp=f"gcc -E")
+        m = generate("", ["--symbol-rules", "yes=__GNUC__"], cpp=f"gcc -E", allow_gnuc=False)
         self.assertFalse(hasattr(m, "__GNUC__"))
 
     @requires_gcc
     def test_override_default_undef(self):
-        m = generate("", ["-X", "__GNUC__", "--symbol-rules", "yes=__GNUC__"], cpp=f"gcc -E")
+        m = generate("", ["--symbol-rules", "yes=__GNUC__"], cpp=f"gcc -E", allow_gnuc=True)
         self.assertIsInstance(m.__GNUC__, int)  # this will be the GCC major version
 
     def test_default_def(self):