Handle cache variables properly in CMake

Author: unclearness

CMakeLists.txt

@@ -248,7 +248,7 @@ endif()
 
 option(UGU_USE_OPENMP "Use OpenMP to enable parallelization" ON)
 if(APPLE)
-set(UGU_USE_OPENMP OFF)
+set(UGU_USE_OPENMP OFF CACHE BOOL "Use OpenMP" FORCE)
 endif()
 message("UGU_USE_OPENMP: ${UGU_USE_OPENMP}")
 if(UGU_USE_OPENMP)
@@ -277,7 +277,7 @@ if(UGU_USE_TBB)
     set(Ugu_LIBS ${Ugu_LIBS} TBB::tbb TBB::tbbmalloc)
   else()
     message(WARNING "TBB not found. Disable UGU_USE_TBB")
-    set(UGU_USE_TBB OFF)
+    set(UGU_USE_TBB OFF CACHE BOOL "Use TBB" FORCE)
   endif()
 endif()
 
@@ -567,7 +567,7 @@ else()
 endif()
 if(APPLE)
   # Not support Apple metal yet
-  set(UGU_BUILD_GUI_APP OFF)
+  set(UGU_BUILD_GUI_APP OFF CACHE BOOL "Switch to build GUI app" FORCE)
 endif()
 message("UGU_BUILD_EXAMPLES: ${UGU_BUILD_EXAMPLES}")
 message("UGU_BUILD_APP: ${UGU_BUILD_APP}")