Contribs: Add xzcat decompression tool

(cherry picked from commit 1fad7fcae5db01e29fc7ed8dd67db76d04752394)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

contrib/src/main.mak

@@ -185,6 +185,10 @@ endif
 ACLOCAL_AMFLAGS += -I$(PREFIX)/share/aclocal
 export ACLOCAL_AMFLAGS
 
+#########
+# Tools #
+#########
+
 PKG_CONFIG ?= pkg-config
 ifdef HAVE_CROSS_COMPILE
 # This inhibits .pc file from within the cross-compilation toolchain sysroot.
@@ -226,6 +230,12 @@ else
 download = $(error Neither curl nor wget found!)
 endif
 
+ifeq ($(shell which xzcat >/dev/null 2>&1 || echo FAIL),)
+XZCAT = xzcat
+else
+XZCAT ?= $(error xz and lzma client not found!)
+endif
+
 ifeq ($(shell which bzcat >/dev/null 2>&1 || echo FAIL),)
 BZCAT = bzcat
 else