Add an option to exclude libuserlayer from host-ipmid

Change-Id: I8e14cfd3719c7fbef739f2aa01771bc4321ce290
Signed-off-by: Ofer Yehielli <ofery@google.com>
Tested: Enabled the exclude libuserlayer flag in
recipes-phosphor/ipmi/phosphor-ipmi-host_%.bbappend
+EXTRA_OECONF_append_xxx = " --disable-libuserlayer"
+HOSTIPMI_PROVIDER_LIBRARY_remove_xxx = "libusercmds.so"
+NETIPMI_PROVIDER_LIBRARY_remove_xxx = "libusercmds.so"
Clean build and test that userlayer.so doesn't get included in the build
diff --git a/configure.ac b/configure.ac
index e13f5e8..869c53d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -192,6 +192,12 @@
 AS_IF([test "x$HOST_IPMI_LIB_PATH" == "x"], [HOST_IPMI_LIB_PATH="/usr/lib/ipmid-providers/"])
 AC_DEFINE_UNQUOTED([HOST_IPMI_LIB_PATH], ["$HOST_IPMI_LIB_PATH"], [The file path to search for libraries.])
 
+# When disable-libuserlayer flag is set, libuserlayer won't be included in the build.
+AC_ARG_ENABLE([libuserlayer],
+    AS_HELP_STRING([--disable-libuserlayer], [Set a flag to exclude libuserlayer])
+)
+AM_CONDITIONAL(FEATURE_LIBUSERLAYER, [test "x$enable_libuserlayer" != "xno"])
+
 # Create configured output
 AC_CONFIG_FILES([
     Makefile