create mode 100644 lib/c/fcntl.zig
 delete mode 100644 lib/libc/musl/src/fcntl/posix_fadvise.c
 delete mode 100644 lib/libc/musl/src/fcntl/posix_fallocate.c
 delete mode 100644 lib/libc/musl/src/linux/fallocate.c