diff --git a/R-package/src/Makevars.win b/R-package/src/Makevars.win
index 3015a1982..b8e5a8089 100644
--- a/R-package/src/Makevars.win
+++ b/R-package/src/Makevars.win
@@ -5,7 +5,7 @@ CXX=`Rcmd config CXX`
 TCFLAGS=`Rcmd config CFLAGS` 
 # expose these flags to R CMD SHLIB
 PKG_CPPFLAGS= -DXGBOOST_CUSTOMIZE_ERROR_ -I$(PKGROOT)  $(SHLIB_OPENMP_CFLAGS)
-XGBFLAG= $(TCFLAGS) -DXGBOOST_CUSTOMIZE_ERROR_ -fPIC  $(SHLIB_OPENMP_CFLAGS)
+GBFLAG= $(TCFLAGS) -DXGBOOST_CUSTOMIZE_ERROR_ -fPIC  $(SHLIB_OPENMP_CFLAGS)
 PKG_LIBS = $(SHLIB_OPENMP_CFLAGS)
 
 ifeq ($(no_omp),1)