The m4 shipped to handle Python was incorrectly clearing

$CPPFLAGS. Additionally, do not repeat compiler flags for automake
targets that already include them, and pass more flags to the Perl build.

Signed-off-by: Kees Cook <kees@ubuntu.com>
Acked-By: Steve Beattie <sbeattie@ubuntu.com>

libraries/libapparmor/m4/ac_python_devel.m4

@@ -158,6 +158,8 @@ $ac_distutils_result])
         AC_MSG_CHECKING([consistency of all components of python development environment])
         AC_LANG_PUSH([C])
         # save current global flags
+        ac_save_LIBS="$LIBS"
+        ac_save_CPPFLAGS="$CPPFLAGS"
         LIBS="$ac_save_LIBS $PYTHON_LDFLAGS"
         CPPFLAGS="$ac_save_CPPFLAGS $PYTHON_CPPFLAGS"
         AC_TRY_LINK([