diff --git a/inst/webr-vars.mk b/inst/webr-vars.mk
index 1e9b299..8fe1b4d 100644
--- a/inst/webr-vars.mk
+++ b/inst/webr-vars.mk
@@ -96,6 +96,9 @@ override DYLIB_LD = $(CC)
 override DYLIB_LDFLAGS = $(CFLAGS)
 override DYLIB_LINK = $(DYLIB_LD) $(DYLIB_LDFLAGS) $(LDFLAGS)
 
+override SHLIB_OPENMP_CFLAGS =
+override SHLIB_OPENMP_CXXFLAGS =
+override SHLIB_OPENMP_FFLAGS =
 override SHLIB_LDFLAGS =
 override SHLIB_LINK = $(SHLIB_LD) $(SHLIB_LDFLAGS) $(LDFLAGS)