fix build on sparc64

Index: cmake/compilers/GNU.cmake
--- cmake/compilers/GNU.cmake.orig
+++ cmake/compilers/GNU.cmake
@@ -119,4 +119,3 @@ endif ()
 
 # TBB malloc settings
 set(TBBMALLOC_LIB_COMPILE_FLAGS -fno-rtti -fno-exceptions)
-set(TBB_OPENMP_FLAG -fopenmp)
