On Windows with gcc (a.k.a. mingw) build as a DLL.
We don't want to hardcode the fonts.conf file location in the DLL, so we
    look up the DLL location at run-time in a DllMain() function. The
    fonts.conf location is deduced from that.
The colon can't be used as path separator on Windows, semicolon is used
    instead. File path components can be separated with either slash or
    backslash. Absolute paths can also begin with a drive letter.
Add internal function FcStrLastSlash that strrchr's the last slash, or
    backslash on Windows.
There is no link() on Windows. For atomicity checks, mkdir a lock directory
    instead.
In addition to HOME, also look for USERPROFILE.
Recognize the special font directory token WINDOWSFONTDIR, to use the
    system's font directory.
Remove the fontconfig-def.cpp that was obsolete. Add fontconfig.def(.in),
    without internal functions.
Add a fontconfig-zip(.in) script, used to build a binary distribution.