update HHVM version.h to 4.21
treec5b225651845aaf8f1a0ccfade05d9e511e2a9c5
-rw-r--r-- 1487 .gitignore
-rw-r--r-- 114 .gitmodules
drwxr-xr-x - CMake
-rw-r--r-- 3931 CMakeLists.txt
-rw-r--r-- 249 CODE_OF_CONDUCT.md
-rw-r--r-- 3334 CONTRIBUTING.md
-rw-r--r-- 637 ISSUE_TEMPLATE.md
-rw-r--r-- 3204 LICENSE.PHP
-rw-r--r-- 2803 LICENSE.ZEND
-rw-r--r-- 2992 README.md
-rw-r--r-- 449 SECURITY.md
-rwxr-xr-x 642 configure
drwxr-xr-x - hphp
drwxr-xr-x - patches
m--------- - third-party