Make improvements

- Introduce portable sched_getcpu() api
- Support GCC's __target_clones__ feature
- Make fma() go faster on x86 in default mode
- Remove some asan checks from core libraries
- WinMain() now ensures $HOME and $USER are defined

libc/str/djbsort.c

@@ -17,7 +17,6 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/dce.h"
-#include "libc/intrin/asan.internal.h"
 #include "libc/nexgen32e/x86feature.h"
 #include "libc/runtime/runtime.h"
 #include "libc/stdckdint.h"
@@ -28,11 +27,6 @@ void djbsort_avx2(int32_t *, long);
  * D.J. Bernstein's outrageously fast integer sorting algorithm.
  */
 void djbsort(int32_t *a, size_t n) {
-  size_t m;
-  if (IsAsan()) {
-    if (ckd_mul(&m, n, 4)) m = -1;
-    __asan_verify(a, m);
-  }
   if (n > 1) {
 #if defined(__x86_64__) && !defined(__chibicc__)
     if (X86_HAVE(AVX2)) {