build: Add AM_PROG_AR to configure.ac
build: Add AM_PROG_AR to configure.ac

Tell Automake that it should import a linker/archiver. This patch fixes the following warnings on Fedora 18:

automake: warnings are treated as errors
/usr/share/automake-1.12/am/ltlibrary.am: warning: 'libhbalinux.la': linking libtool libraries using a non-POSIX
/usr/share/automake-1.12/am/ltlibrary.am: archiver requires 'AM_PROG_AR' in 'configure.ac'
Makefile.am:4:   while processing Libtool library 'libhbalinux.la'

Signed-off-by: Robert Love <ae32029cc3b561e3768d1db8669e99f5bdf25e4b@intel.com>

cleech/libhbalinux,cleech/libhbalinux