Introducing memcchr(3).

It seems two of the file system drivers we have in the tree, namely ufs
and ext3, use a function called `skpc()'. The meaning of this function
does not seem to be documented in FreeBSD, but it turns out one needs to
be a VAX programmer to understand what it does.

SPKC is an instruction on the VAX that does the opposite of memchr(). It
searches for the non-equal character. Add a new function called
memcchr() to the tree that has the following advantages over skpc():

- It has a name that makes more sense than skpc(). Just like strcspn()
  matches the complement of strspn(), memcchr() is the complement of
  memchr().

- It is faster than skpc(). Similar to our strlen() in libc, it compares
  entire words, instead of single bytes. It seems that for this routine
  this yields a sixfold performance increase on amd64.

- It has a man page.

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/conf/files b/sys/conf/files
index 2f8b5f6..871921c 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -2557,6 +2557,7 @@ libkern/inet_ntoa.c		standard
 libkern/inet_ntop.c		standard
 libkern/inet_pton.c		standard
 libkern/mcount.c		optional profiling-routine
+libkern/memcchr.c		standard
 libkern/memcmp.c		standard
 libkern/qsort.c			standard
 libkern/qsort_r.c		standard