force linking zlib to libcurl.dll in static mode
force linking zlib to libcurl.dll in static mode

Switching to MSYS2 (from standalone mingw-w64 toolchain)
caused a regression where zlib was being linked to
libcurl.dll in shared mode, making it depend on MSYS2's
zlib1.dll. This patch makes sure to keep the previous
behavior and link zlib to libcurl.dll in static mode.

vszakats/harbour-deps,vszakats/harbour-deps