contribs: add a52dec library

contrib/src/a52/SHA512SUMS

+4b26fe9492f218b775fb190b76ecf06edaeb656adfe6dcbd24d0a0f86871c3ba917edb88a398eb12dccedaa1605b6f0a0be06b09f9fddd9a46e457b7dd244848  a52dec-0.7.4.tar.gz

contrib/src/a52/rules.mak

+# liba52
+
+A52DEC_VERSION := 0.7.4
+A52DEC_URL := $(CONTRIB_VIDEOLAN)/a52dec-$(A52DEC_VERSION).tar.gz
+
+PKGS += a52
+
+$(TARBALLS)/a52dec-$(A52DEC_VERSION).tar.gz:
+	$(DOWNLOAD) $(A52DEC_URL)
+
+.sum-a52: $(TARBALLS)/a52dec-$(A52DEC_VERSION).tar.gz
+	$(CHECK_SHA512)
+	touch $@
+
+a52dec: $(TARBALLS)/a52dec-$(A52DEC_VERSION).tar.gz .sum-a52
+	$(UNPACK_GZ)
+ifndef HAVE_FPU
+	(cd $@-$(A52DEC_VERSION) && patch -p0) < $(SRC)/a52/liba52-fixed.diff
+endif
+	mv $@-$(A52DEC_VERSION) $@
+	touch $@
+
+.a52: a52dec
+ifdef HAVE_WIN64
+	cd $< && autoreconf -fi
+endif
+	cd $< && $(HOSTVARS) ./configure $(HOSTCONF)
+	cd $</liba52 && $(MAKE) install
+	cd $</include && $(MAKE) install
+	touch $@