MLCE-1271 Enable ACL build with OpenMP as default scheduler.

Signed-off-by: Colm Donelan <colm.donelan@arm.com>
Change-Id: I7d1156812c8765ffccd1cc2cabd4f9450f14f676
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 660b755..a14c500 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -529,8 +529,12 @@
 
 if(ARMCOMPUTENEON OR ARMCOMPUTECL OR ARMCOMPUTEGPUFSA)
     if (BUILD_ACL_OPENMP)
-        target_link_libraries(armnn PUBLIC -fopenmp -static-openmp )
-        target_compile_options(armnn PUBLIC -fopenmp)
+        if (("${CMAKE_SYSTEM_NAME}" STREQUAL Android))
+            target_link_libraries(armnn PUBLIC -fopenmp -static-openmp)
+        else() # Assumes GCC on aarch64.
+            target_compile_options(armnn PUBLIC -fopenmp)
+            target_link_libraries(armnn PUBLIC -lgomp)
+        endif()
     endif()
     target_link_libraries(armnn PUBLIC ${ARMCOMPUTE_LIBRARIES})
 endif()