Introducing dual-licensing-style 'selective licensing' in case VACore is build...

Introducing dual-licensing-style 'selective licensing' in case VACore is build with a dependency to GPL libs (in which case VACore becomes GPL, too)

CMakeLists.txt

@@ -22,6 +22,12 @@ if( NOT DEFINED ITA_VA_BUILD_STATIC )
 	set( ITA_VA_BUILD_STATIC OFF CACHE BOOL "Build static VA libs" )
 endif( )
 
+if( NOT DEFINED ITA_VA_CORE_LIBS_FFT_USES_FFTW3 )
+	set( ITA_VA_CORE_LIBS_FFT_USES_FFTW3 ON CACHE BOOL "If ITAFFT library of ITACoreLibs uses FFTW3, VACore has to fall back to GNU GPL license." )
+	set( ITA_VA_COPYING_GNU_GPL ON PARENT_SCOPE )
+endif( )
+
+
 if( NOT DEFINED ITA_VACORE_DEPLOY_WITH_COMMON_DATA )
 	set( ITA_VACORE_DEPLOY_WITH_COMMON_DATA ON CACHE BOOL "Will deploy VACore with common data (HRIR, Directivity, WAV file, HPEQ, Room Model, etc)" )
 endif( )