With this, src/EDITME as Local/Makefile *only* needs EXIM_USER to be
set and EXIM_MONITOR commented out for Exim to build on my box.
I think this is a reasonable default; if there are releases of PCRE which
do not include pcre-config, then on those boxes a slight change will be
needed, but only where the file was already having to be edited anyway.
# to find the include files and libraries, else use PCRE_LIBS and set INCLUDE
# too if needed.
-# PCRE_CONFIG=yes
+PCRE_CONFIG=yes
# PCRE_LIBS=-lpcre