Simplify cosmocc builds (#863)

- tcgetpgrp(STDIN_FILENO) should be equal to getpgrp() on Windows also,
  found while reading wget source code which uses this check to decide
  whether to print to stderr or to a file
- IN6_ADDR_ARE_EQUAL is a comparison macro used when IPV6 is allowed,
  found while reading CPython3.11 source code
- the changes in signal.h and addition of ucontext.h are because
  CPython3.11 source code expect sigaltstack to be available
- the sqlite3.mk change is because CPython3.11 requires sqlite3 to be
  built with -DOMIT_SHARED_CACHE
- unistd.h has getopt.h now, because some libraries like it there

libc/calls/tcgetpgrp.c

@@ -43,7 +43,7 @@ int tcgetpgrp(int fd) {
   } else if (IsBsd()) {
     rc = sys_ioctl(fd, TIOCGPGRP_bsd, &pgrp);
   } else if (IsWindows()) {
-    rc = getpid();
+    pgrp = rc = getpid();
   } else {
     rc = enosys();
   }

libc/isystem/netinet/in.h

@@ -17,4 +17,11 @@
 #include "libc/sysv/consts/mcast.h"
 #include "libc/sysv/consts/pf.h"
 #include "libc/sysv/consts/sock.h"
+
+# define IN6_ARE_ADDR_EQUAL(a,b) \
+	((((const uint32_t *) (a))[0] == ((const uint32_t *) (b))[0])	      \
+	 && (((const uint32_t *) (a))[1] == ((const uint32_t *) (b))[1])      \
+	 && (((const uint32_t *) (a))[2] == ((const uint32_t *) (b))[2])      \
+	 && (((const uint32_t *) (a))[3] == ((const uint32_t *) (b))[3]))
+
 #endif /* COSMOPOLITAN_LIBC_ISYSTEM_NETINET_IN_H_ */

libc/isystem/signal.h

@@ -3,6 +3,7 @@
 #include "libc/calls/calls.h"
 #include "libc/calls/sigtimedwait.h"
 #include "libc/calls/struct/sigaction.h"
+#include "libc/calls/struct/sigaltstack.h"
 #include "libc/calls/struct/siginfo.h"
 #include "libc/sysv/consts/sa.h"
 #include "libc/sysv/consts/sicode.h"

libc/isystem/sys/ucontext.h

@@ -0,0 +1,4 @@
+#ifndef _SYS_UCONTEXT_H
+#define _SYS_UCONTEXT_H
+#include "libc/calls/ucontext.h"
+#endif /* _SYS_UCONTEXT_H */

libc/isystem/unistd.h

@@ -10,6 +10,7 @@
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/consts/ok.h"
 #include "libc/time/time.h"
+#include "third_party/getopt/long.h"
 #include "third_party/musl/crypt.h"
 #include "third_party/musl/lockf.h"
 #endif /* _UNISTD_H */

third_party/libcxx/csignal

@@ -45,6 +45,7 @@ int raise(int sig);
 #include "libc/calls/struct/sigaction.h"
 #include "libc/calls/struct/siginfo.h"
 #include "libc/sysv/consts/sa.h"
+#include "libc/sysv/consts/sig.h"
 #include "libc/sysv/consts/sicode.h"
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

third_party/sqlite3/sqlite3.mk

@@ -121,7 +121,6 @@ THIRD_PARTY_SQLITE3_FLAGS =						\
 	-DSQLITE_OMIT_UTF16						\
 	-DSQLITE_OMIT_TCL_VARIABLE					\
 	-DSQLITE_OMIT_LOAD_EXTENSION					\
-	-DSQLITE_OMIT_SHARED_CACHE					\
 	-DSQLITE_OMIT_AUTOINIT						\
 	-DSQLITE_OMIT_GET_TABLE						\
 	-DSQLITE_OMIT_COMPILEOPTION_DIAGS                               \