#GCC14 promoted some warnings to errors. This can break #autoconf, #CMake, #Meson or other build environments autoprobing for features, resulting in code built with missing or altered functionality. This could even lead to security impact, if some security related feature is unexpectedly not enabled.
Passing CC as "gcc -fpermissive" should fix this. If this is not an option there's even the nuclear option of adding a gcc wrapper script that does:
#!/bin/sh
exec /usr/bin/gcc -fpermissive "$@"
EDIT: I do not mean to say that these new options should blanket-disabled globally. There however are currently some packages that have problems with GCC 14 (missing features or existing functions not being used, or just failing to build). Naturally these packages should be fixed themselves. Meanwhile -fpermissive will allow building most of these troublesome packages.