Make exciting improvements

- Add Lua backtraces to redbean!
- Wipe serving keys after redbean forks
- Audit redbean to remove free via exit
- Log SSL client ciphersuite preferences
- Increase ASAN malloc() backtrace depth
- Make GetSslRoots() behave as a singleton
- Move leaks.c from LIBC_TESTLIB to LIBC_LOG
- Add undocumented %n to printf() for newlines
- Fix redbean memory leak reindexing inode change
- Fix redbean memory leak with Fetch() DNS object
- Restore original environ after __cxa_finalize()
- Make backtrace always work after __cxa_finalize()
- Introduce COUNTEXPR() diagnostic / benchmark tool
- Fix a few more instances of errno being clobbered
- Consolidate the ANSI color disabling internal APIs

libc/intrin/getenv.c

@@ -0,0 +1,68 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/sysdebug.internal.h"
+#include "libc/dce.h"
+#include "libc/runtime/runtime.h"
+
+forceinline int Identity(int c) {
+  return c;
+}
+
+forceinline int ToUpper(int c) {
+  return 'a' <= c && c <= 'z' ? c - ('a' - 'A') : c;
+}
+
+forceinline char *GetEnv(const char *s, int xlat(int)) {
+  char **p;
+  size_t i, j;
+  if ((p = environ)) {
+    for (i = 0; p[i]; ++i) {
+      for (j = 0;; ++j) {
+        if (!s[j]) {
+          if (p[i][j] == '=') {
+            return p[i] + j + 1;
+          }
+          break;
+        }
+        if (xlat(s[j]) != xlat(p[i][j])) {
+          break;
+        }
+      }
+    }
+  }
+  return 0;
+}
+
+/**
+ * Returns value of environment variable, or NULL if not found.
+ *
+ * Environment variables can store empty string on Unix but not Windows.
+ *
+ * @note should not be used after __cxa_finalize() is called
+ */
+char *getenv(const char *s) {
+  char *r;
+  if (!IsWindows()) {
+    r = GetEnv(s, Identity);
+  } else {
+    r = GetEnv(s, ToUpper);
+  }
+  SYSDEBUG("getenv(%#s) → %#s", s, r);
+  return r;
+}