Set WINVER as well as _WIN32_WINNT.

Change-Id: I6ace26d6c25549cf42755423340af07e96e05779
diff --git a/core/combo/HOST_CROSS_windows-x86.mk b/core/combo/HOST_CROSS_windows-x86.mk
index c2a65bc..1ac1059 100644
--- a/core/combo/HOST_CROSS_windows-x86.mk
+++ b/core/combo/HOST_CROSS_windows-x86.mk
@@ -32,8 +32,8 @@
 $(combo_var_prefix)GLOBAL_CFLAGS += -D__STDC_FORMAT_MACROS -D__STDC_CONSTANT_MACROS
 # Use C99-compliant printf functions (%zd).
 $(combo_var_prefix)GLOBAL_CFLAGS += -D__USE_MINGW_ANSI_STDIO=1
-# Admit to using >= Win2K.
-$(combo_var_prefix)GLOBAL_CFLAGS += -D_WIN32_WINNT=0x0500
+# Admit to using >= Win2K. Both are needed because of <_mingw.h>.
+$(combo_var_prefix)GLOBAL_CFLAGS += -D_WIN32_WINNT=0x0500 -DWINVER=0x0500
 # Get 64-bit off_t and related functions.
 $(combo_var_prefix)GLOBAL_CFLAGS += -D_FILE_OFFSET_BITS=64