https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105404
--- Comment #7 from David Binderman <dcb314 at hotmail dot com> --- (In reply to Martin Liška from comment #6) > Can't see the warning when I build the current zlib library with clang. You might need to switch on -Wall or (more likely) -Wextra. > Can you please paste a build log? Not easily. Here is one example warning, amongst many: ../../trunk.git/zlib/uncompr.c:86:13: warning: a function declaration without a prototype is deprecated in all versions of C and is not supported in C2x [-Wdeprecated-non-prototype] As I say, pattern /zlib/.*-Wdeprecated-non-prototype would probably work.