build: enable automake for extensions/ directory

Because we are likely to be having more userspace programs soon, and
reproducing manual makefiles is a bad idea, make extensions/ ready
for automake traversal. The build pattern now is:

1.  toplevel Makefile.am starts off with extensions/Makefile.am

2.  Makefile.am

    a.  builds programs in current directory

    b.  runs Kbuild
        - only from extensions/Makefile.am
          (so it does not get reinvoked from case 2cII)
        - Kbuild recurses on its own

    c.  runs Mbuild
        I.  builds iptables shared libraries in current directory
        II. runs Makefile.am in each subdir (goto step 2.)

extensions/ipset/Makefile.am

@@ -1,45 +1,9 @@
 # -*- Makefile -*-
 
-AM_CFLAGS       = ${regular_CFLAGS} -DIPSET_LIB_DIR=\"${xtlibdir}\"
+AM_CFLAGS = ${regular_CFLAGS} -DIPSET_LIB_DIR=\"${xtlibdir}\"
+
+include ../../Makefile.extra
 
 sbin_PROGRAMS = ipset
-pkglibexec_LTLIBRARIES = \
-	libipset_iphash.la \
-	libipset_ipmap.la \
-	libipset_ipporthash.la \
-	libipset_ipportiphash.la \
-	libipset_ipportnethash.la \
-	libipset_iptree.la \
-	libipset_iptreemap.la \
-	libipset_macipmap.la \
-	libipset_nethash.la \
-	libipset_portmap.la \
-	libipset_setlist.la
-
 ipset_LDADD   = -ldl
 ipset_LDFLAGS = -rdynamic
-
-module_flags = -avoid-version -module
-
-libipset_iphash_la_SOURCES        = ipset_iphash.c
-libipset_iphash_la_LDFLAGS        = ${module_flags}
-libipset_ipmap_la_SOURCES         = ipset_ipmap.c
-libipset_ipmap_la_LDFLAGS         = ${module_flags}
-libipset_ipporthash_la_SOURCES    = ipset_ipporthash.c
-libipset_ipporthash_la_LDFLAGS    = ${module_flags}
-libipset_ipportiphash_la_SOURCES  = ipset_ipportiphash.c
-libipset_ipportiphash_la_LDFLAGS  = ${module_flags}
-libipset_ipportnethash_la_SOURCES = ipset_ipportnethash.c
-libipset_ipportnethash_la_LDFLAGS = ${module_flags}
-libipset_iptree_la_SOURCES        = ipset_iptree.c
-libipset_iptree_la_LDFLAGS        = ${module_flags}
-libipset_iptreemap_la_SOURCES     = ipset_iptreemap.c
-libipset_iptreemap_la_LDFLAGS     = ${module_flags}
-libipset_macipmap_la_SOURCES      = ipset_macipmap.c
-libipset_macipmap_la_LDFLAGS      = ${module_flags}
-libipset_nethash_la_SOURCES       = ipset_nethash.c
-libipset_nethash_la_LDFLAGS       = ${module_flags}
-libipset_portmap_la_SOURCES       = ipset_portmap.c
-libipset_portmap_la_LDFLAGS       = ${module_flags}
-libipset_setlist_la_SOURCES       = ipset_setlist.c
-libipset_setlist_la_LDFLAGS       = ${module_flags}

extensions/ipset/Mbuild

@@ -0,0 +1,7 @@
+# -*- Makefile -*-
+
+obj-m += $(addprefix lib,$(patsubst %.c,%.so,$(notdir \
+	$(wildcard ${XA_SRCDIR}/ipset_*.c))))
+
+libipset_%.oo: ${XA_SRCDIR}/ipset_%.c
+	${AM_V_CC}${CC} ${AM_DEPFLAGS} ${AM_CFLAGS} -DPIC -fPIC ${CFLAGS} -o $@ -c $<;