diff --git a/libc/include/limits.h b/libc/include/limits.h
index 98307aa6a8..4df636d524 100644
--- a/libc/include/limits.h
+++ b/libc/include/limits.h
@@ -7,9 +7,55 @@
 
 __BEGIN_DECLS
 
-// FIXME: What do I have to define here?
-//        glibc seems to only define numerical
-//        and posix constants
+#define _POSIX_AIO_LISTIO_MAX 2
+#define _POSIX_AIO_MAX 1
+#define _POSIX_ARG_MAX 4096
+#define _POSIX_CHILD_MAX 25
+#define _POSIX_DELAYTIMER_MAX 32
+#define _POSIX_HOST_NAME_MAX 255
+#define _POSIX_LINK_MAX 8
+#define _POSIX_LOGIN_NAME_MAX 9
+#define _POSIX_MAX_CANON 255
+#define _POSIX_MAX_INPUT 255
+#define _POSIX_MQ_OPEN_MAX 8
+#define _POSIX_MQ_PRIO_MAX 32
+#define _POSIX_NAME_MAX 14
+#define _POSIX_NGROUPS_MAX 8
+#define _POSIX_OPEN_MAX 20
+#define _POSIX_PATH_MAX 256
+#define _POSIX_PIPE_BUF 512
+#define _POSIX_RE_DUP_MAX 255
+#define _POSIX_RTSIG_MAX 8
+#define _POSIX_SEM_NSEMS_MAX 256
+#define _POSIX_SEM_VALUE_MAX 32767
+#define _POSIX_SIGQUEUE_MAX 32
+#define _POSIX_SSIZE_MAX 32767
+#define _POSIX_SS_REPL_MAX 4
+#define _POSIX_STREAM_MAX 8
+#define _POSIX_SYMLINK_MAX 255
+#define _POSIX_SYMLOOP_MAX 8
+#define _POSIX_THREAD_DESTRUCTOR_ITERATIONS 4
+#define _POSIX_THREAD_KEYS_MAX 128
+#define _POSIX_THREAD_THREADS_MAX 64
+#define _POSIX_TIMER_MAX 32
+#define _POSIX_TRACE_EVENT_NAME_MAX 30
+#define _POSIX_TRACE_NAME_MAX 8
+#define _POSIX_TRACE_SYS_MAX 8
+#define _POSIX_TRACE_USER_EVENT_MAX 32
+#define _POSIX_TTY_NAME_MAX 9
+#define _POSIX_TZNAME_MAX 6
+#define _POSIX2_BC_BASE_MAX 99
+#define _POSIX2_BC_DIM_MAX 2048
+#define _POSIX2_BC_SCALE_MAX 99
+#define _POSIX2_BC_STRING_MAX 1000
+#define _POSIX2_CHARCLASS_NAME_MAX 14
+#define _POSIX2_COLL_WEIGHTS_MAX 2
+#define _POSIX2_EXPR_NEST_MAX 32
+#define _POSIX2_LINE_MAX 2048
+#define _POSIX2_RE_DUP_MAX 255
+#define _XOPEN_IOV_MAX 16
+#define _XOPEN_NAME_MAX 255
+#define _XOPEN_PATH_MAX 1024
 
 #define OPEN_MAX 64
 #define NAME_MAX 255