contrib: add libdsm (v0.0.2) and its dependency libtasn1 (v3.7)

contrib/src/libdsm/SHA512SUMS

+b1b130a9c48c8908aa63cf7588ef1962ed53093029080fd8a5c5774cb88ed1fd12fe50fef308f88e36516dc3e3ec7ac8046380db0f2b8de2cc01383115002f7f  libdsm-0.0.2.tar.gz

contrib/src/libdsm/rules.mak

+# libdsm
+
+#LIBDSM_GITURL := git://github.com/videolabs/libdsm.git
+LIBDSM_VERSION := 0.0.2
+LIBDSM_URL := https://github.com/videolabs/libdsm/releases/download/v$(LIBDSM_VERSION)/libdsm-$(LIBDSM_VERSION).tar.gz
+
+ifeq ($(call need_pkg,"libdsm"),)
+PKGS_FOUND += libdsm
+endif
+
+$(TARBALLS)/libdsm-$(LIBDSM_VERSION).tar.gz:
+	$(call download,$(LIBDSM_URL))
+
+libdsm: libdsm-$(LIBDSM_VERSION).tar.gz .sum-libdsm
+	$(UNPACK)
+	$(MOVE)
+
+DEPS_libdsm = libtasn1 iconv
+
+.libdsm: libdsm
+	cd $< && $(HOSTVARS) ./configure $(HOSTCONF)
+	cd $< && $(MAKE) install
+	touch $@

contrib/src/libtasn1/SHA512SUMS

+8480507d6bc6b15f4a765d6c268026efd564a07eaacb25388a9c4e67bcba1f0d97f52fc348153f1775f6feecb95113ce067a81b1dc694825c5e178e6cf9a67aa  libtasn1-3.7.tar.gz

contrib/src/libtasn1/rules.mak

+# libtasn1
+
+LIBTASN1_VERSION := 3.7
+LIBTASN1_URL := $(GNU)/libtasn1/libtasn1-$(LIBTASN1_VERSION).tar.gz
+
+ifeq ($(call need_pkg,"libtasn1"),)
+PKGS_FOUND += libtasn1
+endif
+
+$(TARBALLS)/libtasn1-$(LIBTASN1_VERSION).tar.gz:
+	$(call download,$(LIBTASN1_URL))
+
+libtasn1: libtasn1-$(LIBTASN1_VERSION).tar.gz .sum-libtasn1
+	$(UNPACK)
+	$(MOVE)
+
+.libtasn1: libtasn1
+	cd $< && $(HOSTVARS) ./configure $(HOSTCONF)
+	cd $< && $(MAKE) install
+	touch $@