Make numerous improvements

- Python static hello world now 1.8mb
- Python static fully loaded now 10mb
- Python HTTPS client now uses MbedTLS
- Python REPL now completes import stmts
- Increase stack size for Python for now
- Begin synthesizing posixpath and ntpath
- Restore Python \N{UNICODE NAME} support
- Restore Python NFKD symbol normalization
- Add optimized code path for Intel SHA-NI
- Get more Python unit tests passing faster
- Get Python help() pagination working on NT
- Python hashlib now supports MbedTLS PBKDF2
- Make memcpy/memmove/memcmp/bcmp/etc. faster
- Add Mersenne Twister and Vigna to LIBC_RAND
- Provide privileged __printf() for error code
- Fix zipos opendir() so that it reports ENOTDIR
- Add basic chmod() implementation for Windows NT
- Add Cosmo's best functions to Python cosmo module
- Pin function trace indent depth to that of caller
- Show memory diagram on invalid access in MODE=dbg
- Differentiate stack overflow on crash in MODE=dbg
- Add stb_truetype and tools for analyzing font files
- Upgrade to UNICODE 13 and reduce its binary footprint
- COMPILE.COM now logs resource usage of build commands
- Start implementing basic poll() support on bare metal
- Set getauxval(AT_EXECFN) to GetModuleFileName() on NT
- Add descriptions to strerror() in non-TINY build modes
- Add COUNTBRANCH() macro to help with micro-optimizations
- Make error / backtrace / asan / memory code more unbreakable
- Add fast perfect C implementation of μ-Law and a-Law audio codecs
- Make strtol() functions consistent with other libc implementations
- Improve Linenoise implementation (see also github.com/jart/bestline)
- COMPILE.COM now suppresses stdout/stderr of successful build commands

libc/calls/chdir-nt.c

@@ -17,18 +17,21 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/internal.h"
+#include "libc/macros.internal.h"
 #include "libc/nt/errors.h"
 #include "libc/nt/files.h"
+#include "libc/nt/process.h"
 #include "libc/nt/runtime.h"
 #include "libc/nt/synchronization.h"
 #include "libc/sysv/errfuns.h"
 
 textwindows int sys_chdir_nt(const char *path) {
+  uint32_t n;
   int e, ms, len;
-  char16_t path16[PATH_MAX];
+  char16_t path16[PATH_MAX], var[4];
   if ((len = __mkntpath(path, path16)) == -1) return -1;
-  if (path16[len - 1] != u'\\') {
-    if (len + 1 + 1 > PATH_MAX) return enametoolong();
+  if (len && path16[len - 1] != u'\\') {
+    if (len + 2 > PATH_MAX) return enametoolong();
     path16[len + 0] = u'\\';
     path16[len + 1] = u'\0';
   }
@@ -38,7 +41,28 @@ textwindows int sys_chdir_nt(const char *path) {
    */
   for (ms = 1;; ms *= 2) {
     if (SetCurrentDirectory(path16)) {
-      return 0;
+      /*
+       * Now we need to set a magic environment variable.
+       */
+      if ((n = GetCurrentDirectory(ARRAYLEN(path16), path16))) {
+        if (n < ARRAYLEN(path16)) {
+          if (!((path16[0] == '/' && path16[1] == '/') ||
+                (path16[0] == '\\' && path16[1] == '\\'))) {
+            var[0] = '=';
+            var[1] = path16[0];
+            var[2] = ':';
+            var[3] = 0;
+            if (!SetEnvironmentVariable(var, path16)) {
+              return __winerr();
+            }
+          }
+          return 0;
+        } else {
+          return enametoolong();
+        }
+      } else {
+        return __winerr();
+      }
     } else {
       e = GetLastError();
       if (ms <= 512 &&