Fix: [MINGW32] Fix launch on Windows 7 x64

Prior to this commit, the following is observed when running openttd.exe
that was compiled using mingw32 on x86_64:

> The procedure entry point ScriptBreak could not be located in the
  dynamic link library GDI32.dll

The MSDN docs at the below link state that modules using Uniscribe must
first link against usp10 before gdi32 to avoid this issue:

https://msdn.microsoft.com/en-us/library/windows/desktop/dd319118(v=vs.85).aspx

Signed-off-by: Joe Stringer <joe@wand.net.nz>

config.lib

@@ -1562,7 +1562,7 @@ make_cflags_and_ldflags() {
 				LDFLAGS="$LDFLAGS -Wl,--subsystem,windows"
 			fi
 
-			LIBS="$LIBS -lws2_32 -lwinmm -lgdi32 -ldxguid -lole32 -limm32"
+			LIBS="$LIBS -lws2_32 -lwinmm -lusp10 -lgdi32 -ldxguid -lole32 -limm32"
 
 			if [ $cc_version -ge 404 ]; then
 				LDFLAGS_BUILD="$LDFLAGS_BUILD -static-libgcc -static-libstdc++"