Build libzim on windows with werror=false

MSVC throw a lot of warning because we also must re-export stl symbols
used in our exported class.

See [1] and [2] (and links inside) for more information.

Especially [3] which seems to say that we should have issue at link time if
it compatibility issue occurs (and so easily catchable).

So I just remove the `werror=true` for now.

[1] https://stackoverflow.com/questions/16419318/one-way-of-eliminating-c4251-warning-when-using-stl-classes-in-the-dll-interface
[2] https://stackoverflow.com/questions/2132747/warning-c4251-when-building-a-dll-that-exports-a-class-containing-an-atlcstrin

kiwixbuild/dependencies/libzim.py

@@ -34,6 +34,7 @@ class Libzim(Dependency):
             configInfo = self.buildEnv.configInfo
             if neutralEnv("distname") == "Windows":
                 yield "-Dwith_xapian=false"
+                yield "-Dwerror=false"
             if configInfo.build == "android":
                 yield "-DUSE_BUFFER_HEADER=false"
                 yield "-Dstatic-linkage=true"