Download binaries for Windows

[plicease]

Share build seems to fail on Windows (#5). The InfoZip project seems to be pretty dormant. MSYS2 has patches to build unzip, but they are for the msys environment not the mingw environment that Strawberry uses. We should download binaries. There is a 64 bit Intel binary provided by MSYS2 here: that would probably work. Uncertain if there is a 32bit binary as well.

[plicease]

32bit Strawberry seems to have fewer errors, just this one:

win32/../unzpriv.h:1844:16: error: expected identifier or '(' before numeric constant
 #define CR     13        /* '\r' on ASCII machines; must be 13 due to EBCDIC */
                ^~
In file included from win32/../unzpriv.h:586,
                 from win32/../unzip.h:718,
                 from win32/win32.c:57:

so if we could patch that for 32bit Windows and get the 64 bit binary that might solve it.

[plicease]

#7 fixes Windows 32 bit share build. So we can ignore that and just download binary for Windows 64 bit. We can support AMR64 when/if somebody complains :)