Add toybox pgrep/pkill.

This is a better alternative to the toybox ps' simple name filtering.
It's much more scriptable too. And pkill makes one of the common uses
directly available.

Change-Id: I92529b68edd136fb8676029abbcc3a9c4d56f218
diff --git a/generated/config.h b/generated/config.h
index d4545c7..cb21d58 100644
--- a/generated/config.h
+++ b/generated/config.h
@@ -266,8 +266,8 @@
 #define USE_OPENVT(...)
 #define CFG_DEALLOCVT 0
 #define USE_DEALLOCVT(...)
-#define CFG_PGREP 0
-#define USE_PGREP(...)
+#define CFG_PGREP 1
+#define USE_PGREP(...) __VA_ARGS__
 #define CFG_PING 0
 #define USE_PING(...)
 #define CFG_PS 1