kernel-wfp: Add a stub for a Windows Filtering Platform based IPsec backend

src/libcharon/plugins/kernel_wfp/Makefile.am

@@ -0,0 +1,20 @@
+AM_CPPFLAGS = \
+	-I$(top_srcdir)/src/libstrongswan \
+	-I$(top_srcdir)/src/libhydra \
+	-I$(top_srcdir)/src/libcharon
+
+AM_CFLAGS = \
+	$(PLUGIN_CFLAGS)
+
+if MONOLITHIC
+noinst_LTLIBRARIES = libstrongswan-kernel-wfp.la
+else
+plugin_LTLIBRARIES = libstrongswan-kernel-wfp.la
+endif
+
+libstrongswan_kernel_wfp_la_SOURCES = \
+	kernel_wfp_plugin.h kernel_wfp_plugin.c \
+	kernel_wfp_ipsec.h kernel_wfp_ipsec.c
+
+libstrongswan_kernel_wfp_la_LDFLAGS = -module -avoid-version
+libstrongswan_kernel_wfp_la_LIBADD = -lfwpuclnt