Dedicated file for Windows-specific checks

autoconf/m4/windows.m4

@@ -0,0 +1,14 @@
+AC_DEFUN([SM_WINDOWS],
+[
+	# Go for the default install path if $WINSDK_PATH is unset
+dnl	if test -z $WINSDK_PATH; then
+dnl		AC_MSG_WARN(WINSDK_PATH not set. Assuming defaults.)
+dnl		WINSDK_PATH="C:/Program Files/Microsoft SDKs/Windows/v7.1"
+dnl	fi
+	AM_CPPFLAGS="-I$WINSDK_PATH/Include $AM_CPPFLAGS"
+	AM_LDFLAGS="-I$WINSDK_PATH/Lib $AM_LDFLAGS"
+	AC_CHECK_HEADER(windows.h, , AC_MSG_ERROR(Windows SDK not found.))
+dnl _WIN32_WINNT 0x503 = Windows XP SP3
+	AC_CHECK_DECL(PBS_MARQUEE, , [AC_MSG_ERROR(w32api headers too old. This is usually caused by trying to use old (official) MinGW instead of MinGW-W64.)], [#include <windows.h>
+	#include <CommCtrl.h>])
+])