Fix watcher extension

Change the extension name so that it's unique,
add missing sources to the CMake manifest
and update the count of expected extensions.

Author: mszabo-wikia

hphp/runtime/ext/watcher/config.cmake

@@ -1,6 +1,8 @@
 HHVM_DEFINE_EXTENSION("watchman" IMPLICIT
   SOURCES
     ext_watcher.cpp
+    watcher-clock.cpp
+    watcher-options.cpp
   SYSTEMLIB
     ext_watcher.php
   DEPENDS

hphp/util/hphp-config.h.in

@@ -90,7 +90,7 @@ ${HHVM_COMPILES_DEFINE_STRING}
 #endif
 
 #ifdef USE_CMAKE
-# if ${HHVM_EXTENSION_COUNT} != 99
+# if ${HHVM_EXTENSION_COUNT} != 100
 #  error You need to update the config file for the new builtin extension, and add the define to the FB section
 # endif
 ${HHVM_EXTENSIONS_ENABLED_DEFINE_STRING}