Make ERROR a NOTICE, more notes (closes #88)

dev/m4/syslibs.m4

@@ -4,14 +4,18 @@
 # We take system libraries out of arguments to the linker
 # to prevent system libraries from pre-empting custom user
 # library locations.
+# We do not currently have a solution for this on the Mac. (#88)
 # Cf. https://code.google.com/p/exm-issues/issues/detail?id=546
 
 AC_MSG_NOTICE([Generating system-libs.txt])
 
 AC_PATH_PROG([LDCONFIG],[ldconfig],[no],["$PATH:/sbin"])
 if [[ ${LDCONFIG} == no ]]
 then
-    AC_MSG_ERROR([Could not find ldconfig.])
+    AC_MSG_NOTICE([\
+Could not find ldconfig. \
+The linker may use system directories. \
+See /dev/m4/syslib.m4 for more information.])
 fi
 
 if [[ ${USE_MAC} == "no" ]]