peter$ cat configure.ac
AC_INIT
AC_CONFIG_SRCDIR(configure.ac)
AM_INIT_AUTOMAKE(foo,2.1)
AC_PATH_XTRA
AC_CONFIG_FILES(Makefile)
AC_OUTPUT
peter$ cat Makefile.am
bin_PROGRAMS = foo
foo_SOURCES = foo.c
foo_LDADD = $(X_LIBS)
peter$ cat foo.c 
int main() {;}
peter$ ./configure
configure: loading site script /Users/peter/config.site
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for gawk... no
checking for mawk... no
checking for nawk... no
checking for awk... awk
checking whether make sets $(MAKE)... yes
checking for style of include used by make... GNU
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables... 
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking dependency style of gcc... none
checking how to run the C preprocessor... gcc -E
checking for X... libraries /usr/X11R6/lib, headers /usr/X11R6/include
checking whether -R must be followed by a space... no
checking for gethostbyname... yes
checking for connect... yes
checking for remove... yes
checking for shmat... yes
checking for IceConnectionNumber in -lICE... yes
configure: creating ./config.status
config.status: creating Makefile
config.status: executing depfiles commands
peter$ make
gcc -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\"
-DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"foo\"
-DVERSION=\"2.1\" -I. -I.     -g -O2 -c foo.c
gcc  -g -O2   -o foo  foo.o -L/usr/X11R6/lib -R/usr/X11R6/lib 
powerpc-apple-darwin8-gcc-4.0.1: unrecognized option '-R/usr/X11R6/lib'