This is especially necessary since GCC 16.x. ===== $ gcc --version gcc (GCC) 16.2.1 20260819 (Red Hat 16.2.1-2) Copyright (C) 2026 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ===== Without this change, /usr/include/limits.h is not included, hence POSIX constants are not defined: ===== $ echo '#include <limits.h>' | gcc -E -H -isystem ~/git/systemd/src/include/musl - 2>&1 >/dev/null | grep '^\..*limit' . /home/watanabe/git/systemd/src/include/musl/limits.h .. /usr/lib/gcc/x86_64-redhat-linux/16/include/limits.h ... /usr/lib/gcc/x86_64-redhat-linux/16/include/syslimits.h ===== With this change, /usr/include/limits.h is included, thus POSIX constants are defined: ===== $ echo '#include <limits.h>' | gcc -E -H -isystem ~/git/systemd/src/include/musl - 2>&1 >/dev/null | grep '^\..*limit' . /home/watanabe/git/systemd/src/include/musl/limits.h .. /usr/lib/gcc/x86_64-redhat-linux/16/include/limits.h ... /usr/include/limits.h ...... /usr/include/linux/limits.h .. /usr/lib/gcc/x86_64-redhat-linux/16/include/limits.h ===== Replaces #43824.
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