zlibvc.vcxproj Debug x86 and Debug x64 targets do not build

[levicki]

This issue is about contrib\vstudio\vc12\zlibvc.vcxproj project file for Visual Studio 2013,

Debug x86 does not build because of /SAFESEH option, and hand-written assembler code which is not written with safe exception handlers in mind. The build errors are as follows:

match686.obj : error LNK2026: module unsafe for SAFESEH image.
inffas32.obj : error LNK2026: module unsafe for SAFESEH image.
x86\ZlibDllDebug\zlibwapi.dll : fatal error LNK1281: Unable to generate SAFESEH image.

Release x86 is set to /SAFESEH:no so I assume it is OK to do the same for Debug build.

Debug x64 does not build because of wrong path in PreBuildEvent -- command is:

cd ..\..\contrib\masmx64

Instead of:

cd ..\..\masmx64

Wrong path in PreBuildEvent seems to have been introduced in vc11 and exists in vc11, vc12, and vc14 versions of zlibvc.vcxproj file.

Proposed patch to fix both Debug builds (for vc12 version only):
https://gist.github.com/levicki/813dd78a43b3aaf6faaf1ff710bc2753

[levicki]

There is already a pull request here, but only for VS 2015 (vc14):
#353