Make more fixes and improvements

- Remove PAGESIZE constant
- Fix realloc() documentation
- Fix ttyname_r() error reporting
- Make forking more reliable on Windows
- Make execvp() a few microseconds faster
- Make system() a few microseconds faster
- Tighten up the socket-related magic numbers
- Loosen restrictions on mmap() offset alignment
- Improve GetProgramExecutableName() with getenv("_")
- Use mkstemp() as basis for mktemp(), tmpfile(), tmpfd()
- Fix flakes in pthread_cancel_test, unix_test, fork_test
- Fix recently introduced futex stack overflow regression
- Let sockets be passed as stdio to subprocesses on Windows
- Improve security of bind() on Windows w/ SO_EXCLUSIVEADDRUSE

libc/intrin/strace.internal.h

@@ -19,7 +19,9 @@ COSMOPOLITAN_C_START_
 #define STRACE(FMT, ...)                                   \
   do {                                                     \
     if (UNLIKELY(__strace > 0) && strace_enabled(0) > 0) { \
+      ftrace_enabled(-1);                                  \
       __stracef(STRACE_PROLOGUE FMT "\n", ##__VA_ARGS__);  \
+      ftrace_enabled(+1);                                  \
     }                                                      \
   } while (0)
 #else