minimal fixes to visual test, so that it actually builds w/o warnings:

- linux_process.c: add an SDLVisualTest_ScreenshotProcess() stub for
  linux builds succeed.
- action_configparser.c: fixes -Wswitch warnings.
- testharness.c: fixes 'is used uninitialized' warnings for userevents.
- testharness.c: fixes format string argument to 'Force killing...'
- testquit.c: fix type of options array in main().
- windows_screenshot.c: lowercase windows.h header name.
- ran dos2unix on all sources and add missing newlines at files' ends.
- minor adjustments to autotools build system (which actually seems to
  need more surgery for unnecessary stuff...)

visualtest/autogen.sh

@@ -1,12 +1,11 @@
 #!/bin/sh
-#
-# Regenerate configuration files
+
 cp acinclude.m4 aclocal.m4
-found=false
-for autoconf in autoconf autoconf259 autoconf-2.59
-do if which $autoconf >/dev/null 2>&1; then $autoconf && found=true; break; fi
-done
-if test x$found = xfalse; then
-    echo "Couldn't find autoconf, aborting"
-    exit 1
+
+if test "$AUTOCONF"x = x; then
+  AUTOCONF=autoconf
 fi
+
+$AUTOCONF || exit 1
+rm aclocal.m4
+rm -rf autom4te.cache