move HOST_IPMI_LIB_PATH to configure.ac

Per TODO in Makefile.am, move the definition of HOST_IPMI_LIB_PATH from
the Makefile to the configure script.

Change-Id: If39bf1193f4502c239a78e21487566b234b746f8
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/configure.ac b/configure.ac
index 78af3df..a4f407f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -161,6 +161,10 @@
 AS_IF([test "x$POWER_READING_SENSOR" == "x"],[POWER_READING_SENSOR="/usr/share/ipmi-providers/power_reading.json"])
 AC_DEFINE_UNQUOTED([POWER_READING_SENSOR], ["$POWER_READING_SENSOR"], [Power reading sensor configuration file])
 
+AC_ARG_VAR(HOST_IPMI_LIB_PATH, [The file path to search for libraries.])
+AS_IF([test "x$HOST_IPMI_LIB_PATH" == "x"], [HOST_IPMI_LIB_PATH="/usr/lib/host-ipmid/"])
+AC_DEFINE_UNQUOTED([HOST_IPMI_LIB_PATH], ["$HOST_IPMI_LIB_PATH"], [The file path to search for libraries.])
+
 # Create configured output
 AC_CONFIG_FILES([Makefile test/Makefile softoff/Makefile])
 AC_OUTPUT