Fix build failures on macOS

[pypy-vrc]

macOS Sequoia 15.6
darwin 24.6.0
python 3.9.6
node 22.18.0
node-gyp 11.2.0

output:

after bumping zlib to 1.3.1:

added missing line:

+++ vendor/zlib/gzguts.h
@@ -33,4 +33,6 @@
#ifdef _WIN32
#  include <stddef.h>
+#else
+#  include <unistd.h>
#endif

This pull request updates zlib from 1.2.8 (Apr 28, 2013) to 1.3.1 (Jan 22, 2024) and added a single line of code. the build now succeeds, though I'm not sure if this could introduce any compatibility issues.

Anyway, my audio-bot builds and runs fine with this. 😉