diff --git a/R-package/src/Makevars b/R-package/src/Makevars
index e03a15425..e5f386f9b 100644
--- a/R-package/src/Makevars
+++ b/R-package/src/Makevars
@@ -1,9 +1,9 @@
 # package root
 PKGROOT=../../
 # _*_ mode: Makefile; _*_
-PKG_CPPFLAGS= -DXGBOOST_CUSTOMIZE_MSG_ -DXGBOOST_CUSTOMIZE_PRNG_ -I$(PKGROOT)  
-PKG_CXXFLAGS= $(SHLIB_OPENMP_CFLAGS)
-PKG_LIBS = $(SHLIB_OPENMP_CFLAGS)
+PKG_CPPFLAGS= -DXGBOOST_CUSTOMIZE_MSG_ -DXGBOOST_CUSTOMIZE_PRNG_ -Wpedantic -I$(PKGROOT)  
+PKG_CXXFLAGS=
+PKG_LIBS = 
 OBJECTS= xgboost_R.o $(PKGROOT)/wrapper/xgboost_wrapper.o $(PKGROOT)/src/io/io.o $(PKGROOT)/src/gbm/gbm.o $(PKGROOT)/src/tree/updater.o
 
 
diff --git a/src/utils/omp.h b/src/utils/omp.h
index 0380ebd67..933ad97f6 100644
--- a/src/utils/omp.h
+++ b/src/utils/omp.h
@@ -9,13 +9,8 @@
 #include <omp.h>
 #else
 #ifndef DISABLE_OPENMP
-#ifndef _MSC_VER
-#warning "OpenMP is not available, compile to single thread code."\
-		 "You may want to ungrade your compiler to enable OpenMP support,"\
-		 "to get benefit of multi-threading."
-#else
-// TODO add warning for msvc
-#endif
+// use pragma message instead of warning
+#pragma message "Warning: OpenMP is not available, xgboost will be compiled into single thread code. You may want to ungrade your compiler to enable OpenMP support, to get benefit of multi-threading."
 #endif
 inline int omp_get_thread_num() { return 0; }
 inline int omp_get_num_threads() { return 1; }
diff --git a/src/utils/utils.h b/src/utils/utils.h
index 625bc2d48..9d235d82a 100644
--- a/src/utils/utils.h
+++ b/src/utils/utils.h
@@ -19,7 +19,7 @@
 #else
 #ifdef _FILE_OFFSET_BITS
 #if _FILE_OFFSET_BITS == 32
-#warning "FILE OFFSET BITS defined to be 32 bit"
+#pragma message "Warning: FILE OFFSET BITS defined to be 32 bit"
 #endif
 #endif