Fix windows build

[mbt]

When building for Windows (using MingW on Linux), the build fails for three reasons:

• First, the debug macro was incorrect; DEBUG_FMT() allows printf-style but DEBUG() does not. Compiler complained and refused to build.
• Second, the UUID value was "undefined" to the linker, and refusing to generate a DLL as a result. Once the correct UUID headers were included from the Windows APIs, the build succeeded and the DLL was created.
• Third, APIs from setupapi.dll are used, but weren't linked. The -lsetupapi command line flag has been added to fix this.
• Lastly, for some reason I do not quite understand, the mingw toolchain is not making the DLL without the -no-undefined command-line flag being passed to it. Doesn't make much sense to me, since there are no unresolved symbols, but now the DLL builds with a normal "./configure && make" and no extra settings.

These commits allow the mingw-compiled Windows build to work again.

[martinling]

Hi Michael, thanks for sending this. I've made some comments on the individual commits with some requested changes, please make these and update the pull request if you can.

[mbt]

Will do in just a few minutes. Thanks for the feedback.

[mbt]

OK, just pushed new commits. The net impact is cleaner than the commit history; if desired, I can simply cancel this pull request and create a new one with a cleaner commit history. Otherwise, I think I addressed everything. Let me know!

[uwehermann]

Hi, thanks for the fixes! I've merged this upstream into the mainline libserialport repo at http://sigrok.org/gitweb/?p=libserialport.git (I've stashed together some of the commits for nicer history indeed).

The DEBUG_FMT fix was already included in mainline so that got dropped, the rest should be in now.

The -no-undefined is indeed needed for shared builds on Windows (DLLs and Import-DLLs), that's a libtool design choice, I think. It won't build DLLs without -no-undefined at all. I've verified that the current state now builds both for shared and static builds (Linux and Windows).

Cheers!