diff --git a/libcxx/utils/libcxx/test/config.py b/libcxx/utils/libcxx/test/config.py
--- a/libcxx/utils/libcxx/test/config.py
+++ b/libcxx/utils/libcxx/test/config.py
@@ -286,12 +286,6 @@
         support_path = os.path.join(self.libcxx_src_root, 'test/support')
         self.cxx.compile_flags += ['-I' + support_path]
 
-        # On GCC, the libc++ headers cause errors due to throw() decorators
-        # on operator new clashing with those from the test suite, so we
-        # don't enable warnings in system headers on GCC.
-        if self.cxx.type != 'gcc':
-            self.cxx.compile_flags += ['-D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER']
-
         # Add includes for the PSTL headers
         pstl_src_root = self.get_lit_conf('pstl_src_root')
         pstl_obj_root = self.get_lit_conf('pstl_obj_root')
diff --git a/libcxx/utils/libcxx/test/params.py b/libcxx/utils/libcxx/test/params.py
--- a/libcxx/utils/libcxx/test/params.py
+++ b/libcxx/utils/libcxx/test/params.py
@@ -93,9 +93,10 @@
 
   Parameter(name='stdlib', choices=['libc++', 'libstdc++', 'msvc'], type=str, default='libc++',
             help="The C++ Standard Library implementation being tested.",
-            actions=lambda stdlib: [
-              AddFeature(stdlib)
-            ]),
+            actions=lambda stdlib: filter(None, [
+              AddFeature(stdlib),
+              AddCompileFlag('-D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER') if stdlib == 'libc++' else None
+            ])),
 
   Parameter(name='enable_warnings', choices=[True, False], type=bool, default=True,
             help="Whether to enable warnings when compiling the test suite.",