add support for lastmod overlay

configure.in

@@ -220,7 +220,7 @@ OL_ARG_ENABLE(sql,[    --enable-sql	  enable sql backend no|yes|mod], no, [no ye
 
 dnl ----------------------------------------------------------------
 dnl SLAPD Overlay Options
-Overlays="chain denyop dyngroup ppolicy proxycache rwm"
+Overlays="chain denyop dyngroup lastmod ppolicy proxycache rwm"
 
 AC_ARG_WITH(xxslapoverlays,[
 SLAPD Overlay Options:])
@@ -230,6 +230,8 @@ OL_ARG_ENABLE(denyop,[    --enable-denyop  	  Deny Operation overlay no|yes|mod]
 	[no yes mod])
 OL_ARG_ENABLE(dyngroup,[    --enable-dyngroup	  Dynamic Group overlay no|yes|mod], no,
 	[no yes mod])
+OL_ARG_ENABLE(lastmod,[    --enable-lastmod	  Last Modification overlay no|yes|mod], no,
+	[no yes mod])
 OL_ARG_ENABLE(ppolicy,[    --enable-ppolicy	  Password Policy overlay no|yes|mod], no,
 	[no yes mod])
 OL_ARG_ENABLE(proxycache,[    --enable-proxycache	  Proxy Cache overlay no|yes|mod], no,
@@ -469,6 +471,7 @@ BUILD_SQL=no
 BUILD_CHAIN=no
 BUILD_DENYOP=no
 BUILD_DYNGROUP=no
+BUILD_LASTMOD=no
 BUILD_PPOLICY=no
 BUILD_PROXYCACHE=no
 BUILD_RWM=no
@@ -2621,6 +2624,17 @@ if test "$ol_enable_dyngroup" != no ; then
 	AC_DEFINE_UNQUOTED(SLAPD_OVER_DYNGROUP,$MFLAG,[define for Dynamic Group overlay])
 fi
 
+if test "$ol_enable_lastmod" != no ; then
+	BUILD_LASTMOD=$ol_enable_lastmod
+	if test "$ol_enable_lastmod" = mod ; then
+		MFLAG=SLAPD_MOD_DYNAMIC
+		SLAPD_DYNAMIC_OVERLAYS="$SLAPD_DYNAMIC_OVERLAYS lastmod.la"
+	else
+		MFLAG=SLAPD_MOD_STATIC
+	fi
+	AC_DEFINE_UNQUOTED(SLAPD_OVER_LASTMOD,$MFLAG,[define for Last Modification overlay])
+fi
+
 if test "$ol_enable_ppolicy" != no ; then
 	BUILD_PPOLICY=$ol_enable_ppolicy
 	if test "$ol_enable_ppolicy" = mod ; then
@@ -2718,6 +2732,7 @@ dnl overlays
   AC_SUBST(BUILD_CHAIN)
   AC_SUBST(BUILD_DENYOP)
   AC_SUBST(BUILD_DYNGROUP)
+  AC_SUBST(BUILD_LASTMOD)
   AC_SUBST(BUILD_PPOLICY)
   AC_SUBST(BUILD_PROXYCACHE)
   AC_SUBST(BUILD_RWM)