diff --git a/src/Makevars.win b/src/Makevars.win
index 14d215b2..a2054dfc 100644
--- a/src/Makevars.win
+++ b/src/Makevars.win
@@ -1,7 +1,7 @@
 ## -- compiling for OpenMP
-PKG_CFLAGS = $(SHLIB_OPENMP_CFLAGS) -O3
+PKG_CFLAGS = $($(subst OPENMP,OPENMP_CFLAGS,SHLIB_OPENMP)) -O3
 PKG_CXXFLAGS = $(SHLIB_OPENMP_CXXFLAGS) -DSTRICT_R_HEADERS
 ## -- using C++ 11
 # CXX_STD = CXX11
 ## -- linking for OpenMP
-PKG_LIBS = $(SHLIB_OPENMP_CFLAGS)
+PKG_LIBS = $(SHLIB_OPENMP_CXXFLAGS)