+# Sometimes a test group needs to ignore gcc warnings, so it locally
+# sets CFLAGS to this.
+ NO_WERROR_CFLAGS='@CFLAGS@ @WARN_CFLAGS@ @WARN_CFLAGS_TEST@'
+NO_WERROR_CXXFLAGS='@CXXFLAGS@ @WARN_CXXFLAGS@ @WARN_CXXFLAGS_TEST@'
+
+# But most of the time, we want -Werror.
+ CFLAGS="$NO_WERROR_CFLAGS @WERROR_CFLAGS@"
+CXXFLAGS="$NO_WERROR_CXXFLAGS @WERROR_CXXFLAGS@"