firebird/extern/zlib

The zlib.exe is a SFX archive with set of include files required to build
Firebird with zlib support and compiled zlib DLL's for both win32 and x64
architectures.

The source code of zlib library was downloaded from

https://www.zlib.net/zlib131.zip

It was built with VS 2017 compilers using commands specified at win32/Makefile.msc:

win32:
nmake -f win32/Makefile.msc

x64:
nmake -f win32/Makefile.msc

Note, ASM files is not uses in build as it was not updated for a long time, not
officially supported and 32-bit build crashes in simplest test, see:

https://github.com/madler/zlib/issues/41
https://github.com/madler/zlib/issues/200
https://github.com/madler/zlib/issues/223
https://github.com/madler/zlib/issues/249