Boost the maximum frame size.

Lemon gets this error on its Parse() function, at least on FreeBSD 11.1
with its version of Clang.

Change-Id: I4fc1674373af5c0016ee953b61066bf6b24b7ad6
Reviewed-on: https://code.wireshark.org/review/27905
Reviewed-by: Guy Harris <guy@alum.mit.edu>

CMakeLists.txt

@@ -497,7 +497,7 @@ else() # ! MSVC
 		# usage in normal operation.
 		#
 		set(COMMON_WARN_FLAGS ${COMMON_WARN_FLAGS}
-			-Wframe-larger-than=16384
+			-Wframe-larger-than=32768
 		)
 	endif()