twain_32/tests: Link with twain_32.dll.

[Jeremy White]

Francois Gouget wrote:
> ---
> 
> winetest can detect if twain_32.dll is there or not, and if it's missing 
> there's nothing to test anyway. Note that make_makefiles will need to be 
> run.

This patch breaks make crosstest for me:

[apevia:~/w/wine/dlls/twain_32/tests] make crosstest
i586-mingw32msvc-gcc dsm.cross.o     testlist.cross.o -o twain_32_crosstest.exe -L../../../dlls -L../../../dlls/twain_32 -L../../../dlls/user32 -L../../../dlls/gdi32 -L../../../dlls/kernel32 -ltwain_32 -luser32 -lgdi32 -lkernel32   
/usr/lib/gcc/i586-mingw32msvc/4.2.1-sjlj/../../../../i586-mingw32msvc/bin/ld: cannot find -ltwain_32
collect2: ld returned 1 exit status
make: *** [twain_32_crosstest.exe] Error 1

(it also breaks make test for me, but that may be operator error).

But, what's more, I do not see the point.  Twain_32 is not a Microsoft
DLL; it is not present by default on most Windows systems.  Further,
the API specifications are quite clear:  you're supposed to LoadLibrary
Twain32, and all Twain applications I've tested do so.  I don't see the
benefit in making our test behave differently than the recommended
behavior for this DLL.

Cheers,

Jeremy