Make some systemic improvements

- add vdso dump utility
- tests now log stack usage
- rename g_ftrace to __ftrace
- make internal spinlocks go faster
- add conformant c11 atomics library
- function tracing now logs stack usage
- make function call tracing thread safe
- add -X unsecure (no ssl) mode to redbean
- munmap() has more consistent behavior now
- pacify fsync() calls on python unit tests
- make --strace flag work better in redbean
- start minimizing and documenting compiler flags

libc/x/makedirs.c

@@ -29,11 +29,13 @@
 static int MakeDirs(const char *path, unsigned mode, int e) {
   int rc;
   char *dir;
-  if (mkdir(path, mode) != -1) {
+  if (mkdir(path, mode) != -1 || errno == EEXIST) {
     errno = e;
     return 0;
   }
-  if (errno != ENOENT) return -1;
+  if (errno != ENOENT) {
+    return -1;
+  }
   dir = xdirname(path);
   if (strcmp(dir, path)) {
     rc = MakeDirs(dir, mode, e);
@@ -49,6 +51,8 @@ static int MakeDirs(const char *path, unsigned mode, int e) {
 /**
  * Recursively creates directory a.k.a. folder.
  *
+ * This function won't fail if the directory already exists.
+ *
  * @param path is a UTF-8 string, preferably relative w/ forward slashes
  * @param mode can be, for example, 0755
  * @return 0 on success or -1 w/ errno