The existing wxwidgets.props wasn't particularly useful as it couldn't
be used with with wx DLLs when the user project configuration were not
called "DLL Debug" or "DLL Release" (and it makes little sense for the
user application to use "DLL" in its configuration names just because it
happens to use wx as DLL, of course).
It also couldn't be used with the libraries built using nmake with a
custom COMPILER_PREFIX, which, significantly, includes the official MSW
binaries.
Try to fix both problems by checking for the actually existing libraries
and using whichever ones we find. This is somewhat surprising for a
project file to do, but it seems like it should result in the most
useful behaviour in practice as it allows user projects importing this
file to work out of the box in all of the following situations:
- Using official wxMSW binaries.
- Building wxMSW from source without any customization.
- Building wxMSW from source using reasonable custom compiler prefix.
