[CMake] MSYS EXEC_PROGRAM() or EXECUTE_PROCESS() fails

[Brad King]

Peter Visser wrote:
> I just "discovered" cmake, I find cmake easy to setup and it works
> fantastic.
> However, a small problem occurs. I'm using: cmake 2.4-patch3 under
> MSYS-1.0.10.
>  
> The problem occurs when using EXEC_PROGRAM() or EXECUTE_PROCESS().
> Instead of "sh.exe" from MSYS being used to execute the program
> "cmd.exe" from windows is being used.
> This results in an error if the binary doesn't run under windows
> natively e.g. wx-config. ( e.g. FIND_PACKAGE(wxWidgets) will not work)
> It can be solved by
> Changing:
>  EXEC_PROGRAM(wx-config
>         ARGS "--cxxflags"
>         OUTPUT_VARIABLE wxWidgets_CXX_FLAGS
>         RETURN_VALUE RET)
> Into:
>  EXEC_PROGRAM(sh
>         ARGS "wx-config --cxxflags"
>         OUTPUT_VARIABLE wxWidgets_CXX_FLAGS
>         RETURN_VALUE RET)
>  
> Most likely I'm doing something wrong, is there a switch/macro or
> calling cmake with an argument to solve this?

CMake is a windows program that happens to know how to generate MSYS
makefiles.  It does not try to reproduce the native build behavior for
EXEC* commands during processing of CMakeLists.txt code.  Windows
programs do not know how to interpret #! lines in scripts they execute.
 You'll have to  invoke it using the second form.  It should work
everywhere anyway.

-Brad