build: restore build order of modules

iptables(exe) requires libext.a, but extensions/ require libxtables.la
(in iptables/). This circular dependency does not work out, so
separate libxtables into its own directory and put it in front.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
diff --git a/libxtables/Makefile.am b/libxtables/Makefile.am
new file mode 100644
index 0000000..c5795fe
--- /dev/null
+++ b/libxtables/Makefile.am
@@ -0,0 +1,20 @@
+# -*- Makefile -*-
+
+AM_CFLAGS   = ${regular_CFLAGS}
+AM_CPPFLAGS = ${regular_CPPFLAGS} -I${top_builddir}/include -I${top_srcdir}/include -I${top_srcdir}/iptables ${kinclude_CPPFLAGS}
+
+lib_LTLIBRARIES       = libxtables.la
+libxtables_la_SOURCES = xtables.c xtoptions.c
+libxtables_la_LDFLAGS = -version-info ${libxtables_vcurrent}:0:${libxtables_vage}
+libxtables_la_LIBADD  =
+if ENABLE_STATIC
+# With --enable-static, shipped extensions are linked into the main executable,
+# so we need all the LIBADDs here too
+libxtables_la_LIBADD += -lm
+endif
+if ENABLE_SHARED
+libxtables_la_CFLAGS  = ${AM_CFLAGS}
+libxtables_la_LIBADD += -ldl
+else
+libxtables_la_CFLAGS  = ${AM_CFLAGS} -DNO_SHARED_LIBS=1
+endif