[flext] linux: undefined symbol using wrapper

[Patrick Gampp]

Hi,
I wrote some flext-pd-externals which work for Windows(Visual Studio and 
nmake) and Mac(Xcode 4 and makefile). The project files are generated 
with the help of CMake.

Now, I try to port them to Linux using CMake-generated makefiles. Almost 
all the externals work, except of two modules, the customFFT~ and 
customIFFT~. Trying to create these externals in pd, I get the error:

"undefined symbol: RFFT_Destroy".


CustomFFT~ and CustomIFFT~ use a C++ fft-wrapper, which uses a static 
C-lib called libmathlib.a, which contains the symbol RFFT_Destroy.
In the fft-wrapper though, RFFT_Destroy is undefined.

As I wrote, the externals work on the other platforms.
Is there a compiler/linker flag I have to set?

Or does something other come to your mind which could cause the problem?

Thanks,
Patrick