Make important improvements

- Fix preadv() and pwritev() for old distros
- Introduce _npassert() and _unassert() macros
- Prove that file locks work properly on Windows
- Support fcntl(F_DUPFD_CLOEXEC) on more systems

tool/viz/bf.c

@@ -25,6 +25,7 @@
 #include "libc/macros.internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/str/str.h"
+#include "libc/str/tab.internal.h"
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/consts/s.h"
 

tool/viz/bin2asm.c

@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/stdio/stdio.h"
 #include "libc/str/str.h"
+#include "libc/str/tab.internal.h"
 
 #define COLS 8
 

tool/viz/bing.c

@@ -21,6 +21,7 @@
 #include "libc/runtime/runtime.h"
 #include "libc/stdio/stdio.h"
 #include "libc/str/str.h"
+#include "libc/str/tab.internal.h"
 #include "libc/sysv/consts/ex.h"
 #include "libc/sysv/consts/exit.h"
 #include "libc/sysv/consts/fileno.h"

tool/viz/memzoom.c

@@ -41,6 +41,7 @@
 #include "libc/sock/struct/pollfd.h"
 #include "libc/stdio/stdio.h"
 #include "libc/str/str.h"
+#include "libc/str/tab.internal.h"
 #include "libc/str/unicode.h"
 #include "libc/sysv/consts/ex.h"
 #include "libc/sysv/consts/exit.h"

tool/viz/unbing.c

@@ -19,6 +19,7 @@
 #include "libc/calls/calls.h"
 #include "libc/stdio/stdio.h"
 #include "libc/str/str.h"
+#include "libc/str/tab.internal.h"
 
 /**
  * @fileoverview UnBing: Glyphs → Binary.