autotools: a few libtool updates from mainstream

(cherry picked from commit 971508c0d7)

acinclude/ltoptions.m4

@@ -128,7 +128,7 @@ LT_OPTION_DEFINE([LT_INIT], [win32-dll],
 [enable_win32_dll=yes
 
 case $host in
-*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-cegcc*)
+*-*-cygwin* | *-*-mingw* | *-*-windows* | *-*-pw32* | *-*-cegcc*)
   AC_CHECK_TOOL(AS, as, false)
   AC_CHECK_TOOL(DLLTOOL, dlltool, false)
   AC_CHECK_TOOL(OBJDUMP, objdump, false)