Add PAM module stub (build deferred until libpam0g-dev installed)

pam/Makefile

@@ -0,0 +1,13 @@
+CFLAGS ?= -Wall -Wextra -Werror -fPIC -O2
+LIBDIR ?= /usr/lib/$(shell dpkg-architecture -qDEB_HOST_MULTIARCH)/security
+
+pam_ubuntu_fido_pending.so: pam_ubuntu_fido_pending.c
+	$(CC) $(CFLAGS) -shared -o $@ $< -lpam
+
+install: pam_ubuntu_fido_pending.so
+	install -D -m 0644 pam_ubuntu_fido_pending.so $(DESTDIR)$(LIBDIR)/pam_ubuntu_fido_pending.so
+
+clean:
+	rm -f pam_ubuntu_fido_pending.so
+
+.PHONY: install clean