[CMake] Externally hooking a FindXYZ module

[Fernando Cacciola]

Hi people,

It turns out that Mac's Leopard OS needs a fix for OpenGL. The fix 
itself  has been discussed in this list a while back:

http://www.mail-archive.com/cmake@cmake.org/msg09358.html


I need to incorporate that fix into production code, and I don't want to 
distribute my own hacked up version FindOpenGL.cmake, not a real one at
least, so I wonder, is there a way to hook into the find_package behaviour?


The only hack I could come up was stubbing a Find module
in this way:

(1)
At the most top level CMakeLists.txt:

# Save aside the default modules path.
set(ORIGINAL_CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} )

# Prepend a project specific path so my modules take precedence
set(CMAKE_MODULE_PATH "cmake_modules" ${CMAKE_MODULE_PATH} )



(2)
Then at the local cmake_modules folder, add a "FindOpenGL.cmake" stub 
with this:


# Avoid recursion
if ( NOT FIND_OPENGL_WRAPPER )

   set ( FIND_OPENGL_WRAPPER 1 )

   set(SAVED_CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} )

   set(CMAKE_MODULE_PATH ${ORIGINAL_CMAKE_MODULE_PATH} )

   # This calls the real module.
   find_package(OpenGL)

   # Here is the post-processing to "fix" OpenGL for leopard

   if ( OPENGL_FOUND AND APPLE_LEOPARD )

     set (CMAKE_SHARED_LINKER_FLAGS "-Wl,-dylib_file,/System/ 
Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib:/ 
System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib")

   endif()

   # reset the modules path.
   set(CMAKE_MODULE_PATH ${SAVED_CMAKE_MODULE_PATH} )

endif()


Is there a better way??

TIA

Fernando Cacciola