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/mem/putenv.c

@@ -105,10 +105,14 @@ Fail:
   return einval();
 }
 
+static void UnsetenvFree(void *p) {
+  free(p);
+}
+
 /* weakly called by unsetenv() when removing a pointer */
 void __freeenv(void *p) {
   if (once) {
-    __cxa_atexit(free, p, 0);
+    __cxa_atexit(UnsetenvFree, p, 0);
   }
 }