Flex, Bison, and CMake compatibility

[Nicolas Alvarez]

Hi,

I'm trying to change the kdelibs buildsystem to generate Flex and Bison 
parsers at compile time, instead of keeping the generated code in version 
control.

One problem I'm hitting is compatibility with CMake 2.6. The FindFLEX and 
FindBISON modules were introduced in CMake 2.8. Copying the files into 
kdelibs/cmake/modules still fails because they use ${CMAKE_CURRENT_LIST_DIR} 
to include FindPackageStandardArgs, and that variable was also introduced in 
CMake 2.8. (note that I don't plan to make kdelibs install these two 
modules; they're just for kdelibs's own use).

The reason it uses CMAKE_CURRENT_LIST_DIR is to workaround an 
incompatibility hell with FindPackageStandardArgs (interesting read):
http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=c4275592a8

As far as I can tell, we don't have this problem, because the version of 
FindPackageStandardArgs included in kdelibs/cmake/modules is new enough and 
has the "second mode" that FindFLEX and FindBISON use. So a simple 
INCLUDE(FindPackageHandleStandardArgs) would work, or we could prefix it 
with ${kdelibs_SOURCE_DIR}/cmake/modules/ to be 100% sure.


A second problem is that kdelibs already has a FindFlex.cmake (note case!) 
which is pretty different, it only looks for the flex executable and sets a 
variable with its path, but it doesn't have its own fancy targets to run it. 
We would have problems in Windows if cmake/modules contains two modules with 
the same name. And yet we can't just delete FindFlex.cmake, because it's 
*installed*, so we'd break kdelibs source compatibility!

How to solve this second problem?

-- 
Nicolas