InitPNGImage() calls Tcl_ZlibStreamInit() with a NULL interpreter.
If Tcl was (accidentially in my case) configured without HAVE_ZLIB, that function does not check for a NULL interpreter when reporting an error and crashes.
Don Porter fixed this on the Tcl side of things with commit https://core.tcl.tk/tcl/info/877c8ac162
(We don't want to pass in a non-NULL interp as we don't want a command creating for the stream.)
Sign up for the SourceForge newsletter:
You seem to have CSS turned off.
Please don't fill out this field.