use $UNTAR instead of hard-coded tar in rule.

diff --git a/contrib/tools/xmlformat/Makefile b/contrib/tools/xmlformat/Makefile
index 1b998fcdcdecad1e1dae21681c4a27177d781592..4489c4735a4250f3971bd751167a58d0c2c017ad 100644 (file)
--- a/contrib/tools/xmlformat/Makefile
+++ b/contrib/tools/xmlformat/Makefile
@@ -8,10 +8,13 @@ EXTRACTED_DIR ?= $(basename $(basename $(DOWNLOAD_FILENAME)))
 WGET ?= wget
 WGET_OPTS ?=
 
+UNTAR ?= tar
+UNTAR_OPTS ?= xvfz
+
 all: $(EXTRACTED_DIR)
 
 $(EXTRACTED_DIR): $(DOWNLOAD_FILENAME)
-       tar xvfz $<
+       $(UNTAR) $(UNTAR_OPTS) $<
 
 $(DOWNLOAD_FILENAME):
        $(WGET) $(DOWNLOAD_URL)/$@