coccinelle: work around a bug in zlib.h parsing

Currently, parsing zlib.h on Fedora (and possibly others) causes spatch
to fail with an assertion. Let's work around that by defining two extra
macros in our Coccinelle parsing hacks.

coccinelle/parsing_hacks.h

@@ -81,3 +81,8 @@
  * let's help it a little here by providing simplified one-line versions. */
 #define CMSG_BUFFER_TYPE(x) union { uint8_t align_check[(size) >= CMSG_SPACE(0) && (size) == CMSG_ALIGN(size) ? 1 : -1]; }
 #define SD_ID128_MAKE(...) ((const sd_id128) {})
+
+/* Work around a bug in zlib.h parsing on Fedora (and possibly others)
+ * See: https://github.com/coccinelle/coccinelle/issues/413 */
+#define Z_EXPORT
+#define Z_EXTERN