Improve cosmo's conformance to libc-test

This change addresses various open source compatibility issues, so that
we pass 313/411 of the tests in https://github.com/jart/libc-test where
earlier today we were passing about 30/411 of them, due to header toil.
Please note that Glibc only passes 341/411 so 313 today is pretty good!

- Make the conformance of libc/isystem/ headers nearly perfect
- Import more of the remaining math library routines from Musl
- Fix inconsistencies with type signatures of calls like umask
- Write tests for getpriority/setpriority which work great now
- conform to `struct sockaddr *` on remaining socket functions
- Import a bunch of uninteresting stdlib functions e.g. rand48
- Introduce readdir_r, scandir, pthread_kill, sigsetjmp, etc..

Follow the instructions in our `tool/scripts/cosmocc` toolchain to run
these tests yourself. You use `make CC=cosmocc` on the test repository

libc/isystem/sys/socket.h

@@ -1,5 +1,6 @@
 #ifndef LIBC_ISYSTEM_SYS_SOCKET_H_
 #define LIBC_ISYSTEM_SYS_SOCKET_H_
+#include "libc/calls/weirdtypes.h"
 #include "libc/sock/sock.h"
 #include "libc/sock/struct/linger.h"
 #include "libc/sock/struct/msghdr.h"

libc/isystem/sys/statvfs.h

@@ -1,5 +1,6 @@
 #ifndef COSMOPOLITAN_LIBC_ISYSTEM_STATVFS_H_
 #define COSMOPOLITAN_LIBC_ISYSTEM_STATVFS_H_
 #include "libc/calls/struct/statvfs.h"
+#include "libc/calls/weirdtypes.h"
 #include "libc/sysv/consts/st.h"
 #endif /* COSMOPOLITAN_LIBC_ISYSTEM_STATVFS_H_ */

libc/isystem/sys/time.h

@@ -1,7 +1,9 @@
 #ifndef LIBC_ISYSTEM_SYS_TIME_H_
 #define LIBC_ISYSTEM_SYS_TIME_H_
-#include "libc/calls/struct/timeval.h"
 #include "libc/calls/struct/itimerval.h"
+#include "libc/calls/struct/timeval.h"
+#include "libc/calls/weirdtypes.h"
+#include "libc/sock/select.h"
 #include "libc/sysv/consts/clock.h"
 #include "libc/sysv/consts/itimer.h"
 #include "libc/time/struct/timezone.h"

libc/isystem/sys/times.h

@@ -2,4 +2,5 @@
 #define COSMOPOLITAN_LIBC_ISYSTEM_SYS_TIMES_H_
 #include "libc/calls/calls.h"
 #include "libc/calls/struct/tms.h"
+#include "libc/calls/weirdtypes.h"
 #endif /* COSMOPOLITAN_LIBC_ISYSTEM_SYS_TIMES_H_ */

libc/isystem/sys/types.h

@@ -2,11 +2,12 @@
 #define LIBC_ISYSTEM_SYS_TYPES_H_
 #include "libc/calls/makedev.h"
 #include "libc/calls/weirdtypes.h"
+#include "libc/thread/thread.h"
 
 #if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
-#include "libc/intrin/newbie.h"
 #include "libc/calls/typedef/u.h"
 #include "libc/calls/weirdtypes.h"
+#include "libc/intrin/newbie.h"
 #include "libc/sock/select.h"
 #include "libc/sysv/consts/endian.h"
 #endif

libc/isystem/sys/uio.h

@@ -1,4 +1,5 @@
 #ifndef COSMOPOLITAN_LIBC_ISYSTEM_SYS_UIO_H_
 #define COSMOPOLITAN_LIBC_ISYSTEM_SYS_UIO_H_
 #include "libc/calls/calls.h"
+#include "libc/calls/struct/iovec.h"
 #endif /* COSMOPOLITAN_LIBC_ISYSTEM_SYS_UIO_H_ */

libc/isystem/sys/un.h

@@ -1,4 +1,6 @@
 #ifndef COSMOPOLITAN_LIBC_ISYSTEM_SYS_UN_H_
 #define COSMOPOLITAN_LIBC_ISYSTEM_SYS_UN_H_
+#include "libc/calls/weirdtypes.h"
 #include "libc/sock/sock.h"
+#include "libc/sock/struct/sockaddr.h"
 #endif /* COSMOPOLITAN_LIBC_ISYSTEM_SYS_UN_H_ */

libc/isystem/sys/wait.h

@@ -1,6 +1,8 @@
 #ifndef LIBC_ISYSTEM_SYS_WAIT_H_
 #define LIBC_ISYSTEM_SYS_WAIT_H_
 #include "libc/calls/calls.h"
+#include "libc/calls/struct/siginfo.h"
 #include "libc/calls/weirdtypes.h"
 #include "libc/sysv/consts/w.h"
+#include "libc/sysv/consts/waitid.h"
 #endif