Implement more security stuff

- Support deterministic stacks on OpenBSD
- Support OpenBSD system call origin verification
- Fix overrun by one in chibicc string token allocator
- Get all chibicc tests passing under Address Sanitizer

libc/calls/chmod.c

@@ -42,7 +42,6 @@
  * @errors ENOENT, ENOTDIR, ENOSYS
  * @asyncsignalsafe
  * @see fchmod()
- * @syscall
  */
 int chmod(const char *pathname, uint32_t mode) {
   if (!pathname) return efault();

libc/calls/clock_gettime.c

@@ -50,7 +50,6 @@
  *     errno isn't restored to its original value, to detect prec. loss
  * @see strftime(), gettimeofday()
  * @asyncsignalsafe
- * @syscall
  */
 int clock_gettime(int clockid, struct timespec *out_ts) {
   /* TODO(jart): Just ignore O/S for MONOTONIC and measure RDTSC on start */

libc/calls/fadvise.c

@@ -29,7 +29,6 @@
  * @param len 0 means ‘til end of file
  * @param advice can be MADV_SEQUENTIAL, MADV_RANDOM, etc.
  * @return -1 on error
- * @syscall
  */
 int fadvise(int fd, uint64_t offset, uint64_t len, int advice) {
   if (!IsWindows()) {

libc/calls/fallocate.c

@@ -38,7 +38,6 @@
  * @return 0 on success, or -1 w/ errno
  * @note limited availability on rhel5 and openbsd
  * @see ftruncate()
- * @syscall
  */
 int fallocate(int fd, int32_t mode, int64_t offset, int64_t length) {
   int rc;

libc/calls/fchmod.c

@@ -40,7 +40,6 @@
  * @errors ENOSYS
  * @asyncsignalsafe
  * @see chmod()
- * @syscall
  */
 int fchmod(int fd, uint32_t mode) {
   /* TODO(jart): Windows */

libc/calls/fchown.c

@@ -28,7 +28,6 @@
  * @return 0 on success, or -1 w/ errno
  * @see /etc/passwd for user ids
  * @see /etc/group for group ids
- * @syscall
  */
 int fchown(int fd, uint32_t uid, uint32_t gid) {
   /* TODO(jart): Windows? */

libc/calls/fcntl.c

@@ -29,7 +29,6 @@
  * @param arg can be FD_CLOEXEC, etc. depending
  * @return 0 on success, or -1 w/ errno
  * @asyncsignalsafe
- * @syscall
  */
 int fcntl(int fd, int cmd, ...) {
   va_list va;

libc/calls/fdatasync.c

@@ -26,7 +26,6 @@
  * @return 0 on success, or -1 w/ errno
  * @see fsync(), sync_file_range()
  * @asyncsignalsafe
- * @syscall
  */
 int fdatasync(int fd) {
   if (!IsWindows()) {

libc/calls/hefty/vfork.S

@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/dce.h"
 #include "libc/macros.h"
+.text.syscall
 
 /	Forks process without copying page tables.
 /

libc/calls/mprotect.greg.c

@@ -34,7 +34,7 @@ extern __msabi typeof(VirtualProtect) *const __imp_VirtualProtect;
  * @return 0 on success, or -1 w/ errno
  * @see mmap()
  */
-int mprotect(void *addr, uint64_t len, int prot) {
+textsyscall int mprotect(void *addr, uint64_t len, int prot) {
   bool cf;
   int64_t rc;
   uint32_t oldprot;