[root@109343-web1 apache2]# apxs -cia mod_security2.c 
/bin/sh /usr/lib/apr/build/libtool --silent --mode=compile gcc -prefer-pic -O2 -g -pipe -m32 -march=i386 -mtune=pentium4 -DAP_HAVE_DESIGNATED_INITIALIZER -DLINUX=2 -D_REENTRANT -D_GNU_SOURCE -pthread -I/usr/include/apr-0 -I/usr/include/httpd  -c -o mod_security2.lo mod_security2.c && touch mod_security2.slo
In file included from modsecurity.h:37,
                 from mod_security2.c:18:
msc_pcre.h:18:18: pcre.h: No such file or directory
apxs:Error: Command failed with rc=65536
.
[root@109343-web1 apache2]# rpm -q pcre-devel 
pcre-devel-4.5-3.2.RHEL4
[root@109343-web1 apache2]# rpm -ql pcre-devel | grep pcre.h
/usr/include/pcre/pcre.h
[root@109343-web1 apache2]# cat /etc/ld.so.conf.d/pcre.conf 
/usr/include/pcre
[root@109343-web1 apache2]# ls -l /usr/include/pcre/pcre.h
-rw-r--r--  1 root root 7038 Aug 19  2005 /usr/include/pcre/pcre.h
[root@109343-web1 apache2]#