Re-apply Megasource-specific CMake patches to zlib.

libs/zlib-1.2.12/CMakeLists.txt

@@ -187,6 +187,10 @@ add_library(zlib SHARED ${ZLIB_SRCS} ${ZLIB_ASMS} ${ZLIB_DLL_SRCS} ${ZLIB_PUBLIC
 add_library(zlibstatic STATIC ${ZLIB_SRCS} ${ZLIB_ASMS} ${ZLIB_PUBLIC_HDRS} ${ZLIB_PRIVATE_HDRS})
 set_target_properties(zlib PROPERTIES DEFINE_SYMBOL ZLIB_DLL)
 set_target_properties(zlib PROPERTIES SOVERSION 1)
+target_include_directories(zlib PUBLIC .)
+target_include_directories(zlib PUBLIC ${CMAKE_CURRENT_BINARY_DIR})
+target_include_directories(zlibstatic PUBLIC .)
+target_include_directories(zlibstatic PUBLIC ${CMAKE_CURRENT_BINARY_DIR})
 
 if(NOT CYGWIN)
     # This property causes shared libraries on Linux to have the full version
@@ -230,6 +234,8 @@ endif()
 # Example binaries
 #============================================================================
 
+return()
+
 add_executable(example test/example.c)
 target_link_libraries(example zlib)
 add_test(example example)