* Add missing linux/stddef.h includes * Explicitly cast PAGE_SIZE to size_t. PAGE_SIZE is defined without UL suffix in musl * Musl doesn't define PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP, so initialize the mutexes with pthread_once.
UTIME_NOW is defined in <sys/stat.h> on glibc and musl. Else, we just need a few headers to get glibc's <sys/cdefs.h> crud.