Get Fabrice Bellard's JavaScript engine to build

$ m=tiny
$ make -j12 MODE=$m o/$m/third_party/quickjs/qjs.com
$ o/$m/third_party/quickjs/qjs.com -e 'console.log(2 + 2)'
4
$ ls -hal o/$m/third_party/quickjs/qjs.com
631.5K

See #97

third_party/quickjs/libbf.c

@@ -1,6 +1,6 @@
 /*
  * Tiny arbitrary precision floating point library
- * 
+ *
  * Copyright (c) 2017-2021 Fabrice Bellard
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -21,19 +21,25 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
-#include <stdlib.h>
-#include <stdio.h>
-#include <inttypes.h>
-#include <math.h>
-#include <string.h>
-#include <assert.h>
+#include "libc/assert.h"
+#include "libc/inttypes.h"
+#include "libc/stdio/stdio.h"
+#include "libc/str/str.h"
+#include "third_party/quickjs/cutils.h"
+#include "third_party/quickjs/libbf.h"
 
+asm(".ident\t\"\\n\\n\
+QuickJS (MIT License)\\n\
+Copyright (c) 2017-2021 Fabrice Bellard\\n\
+Copyright (c) 2017-2021 Charlie Gordon\"");
+asm(".include \"libc/disclaimer.inc\"");
+
+/* TODO(jart): let's use asm() instead of intel's strange and unusual veneer */
 #ifdef __AVX2__
-#include <immintrin.h>
+#undef __AVX2__
 #endif
 
-#include "cutils.h"
-#include "libbf.h"
+/* clang-format off */
 
 /* enable it to check the multiplication result */
 //#define USE_MUL_CHECK