Windows: Always set the system timer resolution to 1ms by default.

An existing hint lets apps that don't need the timer resolution changed avoid
this, to save battery, etc, but this fixes several problems in timing, audio
callbacks not firing fast enough, etc.

Fixes Bugzilla #2944.

build-scripts/updaterev.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+#
+# Generate a header file with the current source revision
+
+outdir=`pwd`
+cd `dirname $0`
+srcdir=..
+header=$outdir/include/SDL_revision.h
+
+rev=`sh showrev.sh 2>/dev/null`
+if [ "$rev" != "" -a "$rev" != "hg-0:baadf00d" ]; then
+    revnum=`echo $rev | sed 's,hg-\([0-9]*\).*,\1,'`
+    echo "#define SDL_REVISION \"$rev\"" >"$header.new"
+    echo "#define SDL_REVISION_NUMBER $revnum" >>"$header.new"
+    if diff $header $header.new >/dev/null 2>&1; then
+        rm "$header.new"
+    else
+        mv "$header.new" "$header"
+    fi
+fi