1 files changed, 3 insertions, 2 deletions
diff --git a/Makefile.mgw b/Makefile.mgw
index 762b05b711..6f53efd55d 100644
--- a/Makefile.mgw
+++ b/Makefile.mgw
@@ -58,8 +58,9 @@
 .PHONY : all libgl clean realclean
 
 CPU ?= pentium
-
-CFLAGS = -Wall -W -pedantic
+
+# when -std=c99 mingw will not define WIN32
+CFLAGS = -Wall -W -Werror -pedantic -std=c99 -DWIN32
 CFLAGS += -O2 -ffast-math -mcpu=$(CPU)
 
 export CFLAGS