MEDIUM: regex: Use PCRE JIT in acl

This is a patch for using PCRE JIT in acl.

I notice regex are used in other places, but they are more complicated
to modify to use PCRE APIs. So I focused to acl in the first try.

BTW, I made a simple benchmark program for PCRE JIT beforehand.
https://github.com/hnakamur/pcre-jit-benchmark

I read the manual for PCRE JIT
http://www.manpagez.com/man/3/pcrejit/

and wrote my benchmark program.
https://github.com/hnakamur/pcre-jit-benchmark/blob/master/test-pcre.c
diff --git a/Makefile b/Makefile
index a78e9d9..daa64ee 100644
--- a/Makefile
+++ b/Makefile
@@ -14,6 +14,7 @@
 #   USE_MY_SPLICE        : redefine the splice syscall if build fails without.
 #   USE_NETFILTER        : enable netfilter on Linux. Automatic.
 #   USE_PCRE             : enable use of libpcre for regex. Recommended.
+#   USE_PCRE_JIT         : enable use of libpcre jit for regex. Recommended.
 #   USE_POLL             : enable poll(). Automatic.
 #   USE_PRIVATE_CACHE    : disable shared memory cache of ssl sessions.
 #   USE_REGPARM          : enable regparm optimization. Recommended on x86.
@@ -521,7 +522,7 @@
 endif
 endif
 
-ifneq ($(USE_PCRE)$(USE_STATIC_PCRE),)
+ifneq ($(USE_PCRE)$(USE_STATIC_PCRE)$(USE_PCRE_JIT),)
 # PCREDIR is used to automatically construct the PCRE_INC and PCRE_LIB paths,
 # by appending /include and /lib respectively. If your system does not use the
 # same sub-directories, simply force these variables instead of PCREDIR. It is
@@ -546,6 +547,10 @@
 OPTIONS_LDFLAGS += $(if $(PCRE_LIB),-L$(PCRE_LIB)) -Wl,-Bstatic -lpcreposix -lpcre -Wl,-Bdynamic
 BUILD_OPTIONS   += $(call ignore_implicit,USE_STATIC_PCRE)
 endif
+# JIT PCRE
+ifneq ($(USE_PCRE_JIT),)
+OPTIONS_CFLAGS  += -DUSE_PCRE_JIT
+endif
 endif
 
 # This one can be changed to look for ebtree files in an external directory