pkg-infra: move the bzr download helper to a script

Maintaining the download helpers in the Makefile has proved to be a bit
complex, so move it to a shell script.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/pkg-download.mk

@@ -11,7 +11,7 @@
 export WGET := $(call qstrip,$(BR2_WGET)) $(QUIET)
 export SVN := $(call qstrip,$(BR2_SVN))
 export CVS := $(call qstrip,$(BR2_CVS))
-BZR := $(call qstrip,$(BR2_BZR))
+export BZR := $(call qstrip,$(BR2_BZR))
 export GIT := $(call qstrip,$(BR2_GIT))
 export HG := $(call qstrip,$(BR2_HG)) $(QUIET)
 SCP := $(call qstrip,$(BR2_SCP)) $(QUIET)
@@ -101,7 +101,7 @@ endef
 
 define DOWNLOAD_BZR
 	test -e $(DL_DIR)/$($(PKG)_SOURCE) || \
-	$(BZR) export $(DL_DIR)/$($(PKG)_SOURCE) $($(PKG)_SITE) -r $($(PKG)_DL_VERSION)
+	$(EXTRA_ENV) support/download/bzr $($(PKG)_SITE) $($(PKG)_DL_VERSION) $(DL_DIR)/$($(PKG)_SOURCE)
 endef
 
 define SOURCE_CHECK_BZR

support/download/bzr

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+# We want to catch any command failure, and exit immediately
+set -e
+
+# Download helper for bzr
+# Call it with:
+#   $1: bzr repo
+#   $2: bzr revision
+#   $3: output file
+# And this environment:
+#   BZR       : the bzr command to call
+#   BR2_DL_DIR: path to Buildroot's download dir
+
+repo="${1}"
+rev="${2}"
+output="${3}"
+
+${BZR} export "${output}" "${repo}" -r "${rev}"