[Gpsbabel-code] [PATCH] Configure-time check for Windows DDK

[Fabrizio G. <fab...@ti...>]

Hello.
When compiling gpsbabel with MinGW, delbin.c assumes that DDK is 
present. That happens even in --with-libusb=no is passed to configure.

This patch adds a configure-time for the presence of the Windows DDK, 
and only compiles the chunk of delbin.c depending on the Windows DDK if 
the check succeeds. This allows successful compilation even if DDK is 
not installed.  It also makes small fixes to configure-time checks for 
Expat and Linux HID.

Regards,
Fabrizio