Add signify port.

ports/signify/signify.patch

@@ -0,0 +1,15 @@
+diff -Paur --no-dereference -- signify.upstream/Makefile signify/Makefile
+--- signify.upstream/Makefile
++++ signify/Makefile
+@@ -1,7 +1,7 @@
+-include ../../build-aux/platform.mak
+-include ../../build-aux/compiler.mak
+-include ../../build-aux/version.mak
+-include ../../build-aux/dirs.mak
++include ../../../build-aux/platform.mak
++include ../../../build-aux/compiler.mak
++include ../../../build-aux/version.mak
++include ../../../build-aux/dirs.mak
+ 
+ OPTLEVEL?=$(DEFAULT_OPTLEVEL)
+ CFLAGS?=$(OPTLEVEL)

ports/signify/signify.port

@@ -0,0 +1,11 @@
+NAME=signify
+BUILD_LIBRARIES=
+VERSION=2017-04-10
+DISTNAME=$NAME-$VERSION
+COMPRESSION=tar.xz
+ARCHIVE=$DISTNAME.$COMPRESSION
+SHA256SUM=0b423119a27a69d417bb67cd38ccfb03d2a7387706911ee04e5d3c3f50e3619b
+UPSTREAM_SITE=https://pub.sortix.org/fork/signify
+UPSTREAM_ARCHIVE=$ARCHIVE
+BUILD_SYSTEM=makefile
+VERSION_REGEX='([0-9]{4}-[0-9]{2}-[0-9]{2})'