Building glib-2.36.2 on OS X 10.7 with clang-4.2 (from xcode-4.6.2):

clang -DHAVE_CONFIG_H -I. -I.. -I.. -I../glib -I../glib -I.. -DG_LOG_DOMAIN=\"GLib\" -DG_DISABLE_CAST_CHECKS -DGLIB_COMPILATION -DPCRE_STATIC -I/sw/include -Wall -Wstrict-prototypes -Werror=declaration-after-statement -Werror=missing-prototypes -Werror=implicit-function-declaration -Werror=pointer-arith -Werror=init-self -Werror=format-security -Werror=format=2 -Werror=missing-include-dirs -Os -c gmarkup.c  -fno-common -DPIC -o .libs/libglib_2_0_la-gmarkup.o

gmarkup.c:2432:31: error: format string is not a string literal

      [-Werror,-Wformat-nonliteral]
  output1 = g_strdup_vprintf (format1->str, args);

                              ^~~~~~~~~~~~

gmarkup.c:2439:31: error: format string is not a string literal
      [-Werror,-Wformat-nonliteral]

  output2 = g_strdup_vprintf (format2->str, args2);

                              ^~~~~~~~~~~~
2 errors generated.