I think I already am, here is an example of one of the calls to gcc:

gcc -I/usr/src/redhat/BUILD/freeradius-server-2.2.3 -I/usr/src/redhat/BUILD/freeradius-server-2.2.3/src -O2 -g -m64 -mtune=generic -fno-strict-aliasing -fPIC -fPIE -DPIE -Wall -D_GNU_SOURCE -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS -DNDEBUG -DWITH_SYSTEM_LTDL -D_LIBRADIUS -I/usr/src/redhat/BUILD/freeradius-server-2.2.3/src -c dhcp.c -o dhcp.o >/dev/null 2>&1

The section from the .spec file is

%ifarch s390 s390x

export CFLAGS="$RPM_OPT_FLAGS -fno-strict-aliasing -fPIC -fPIE -DPIE"

export LDFLAGS="-pie -Wl,-znow"

%else

export CFLAGS="$RPM_OPT_FLAGS -fno-strict-aliasing -fpic -fPIE -DPIE"

export LDFLAGS="-pie -Wl,-znow"

%endif

From: freeradius-users-bounces+adrian.p.smith=bt.com@lists.freeradius.org [mailto:freeradius-users-bounces+adrian.p.smith=bt.com@lists.freeradius.org] On Behalf Of Alan Buxey
Sent: 25 January 2014 18:06
To: FreeRadius users mailing list
Subject: Re: trouble building RPM

Build the RPM with the fPIC option? You'll need to edit the spec file