build: add support for choosing a different url filename part than the output file

Backport of r47591 and r48427

patches/openwrt/0006-build-add-support-for-choosing-a-different-url-filename-part-than-the-output-file.patch

+From: Matthias Schiffer <mschiffer@universe-factory.net>
+Date: Tue, 9 Feb 2016 13:49:01 +0100
+Subject: build: add support for choosing a different url filename part than the output file
+
+Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+
+Backport of r47591 and r48427
+
+diff --git a/include/download.mk b/include/download.mk
+index 937b5d3..e518cce 100644
+--- a/include/download.mk
++++ b/include/download.mk
+@@ -44,11 +44,11 @@ define DownloadMethod/unknown
+ endef
+ 
+ define DownloadMethod/default
+-	$(SCRIPT_DIR)/download.pl "$(DL_DIR)" "$(FILE)" "$(MD5SUM)" $(foreach url,$(URL),"$(url)")
++	$(SCRIPT_DIR)/download.pl "$(DL_DIR)" "$(FILE)" "$(MD5SUM)" "$(URL_FILE)" $(foreach url,$(URL),"$(url)")
+ endef
+ 
+ define wrap_mirror
+-	$(if $(if $(MIRROR),$(filter-out x,$(MIRROR_MD5SUM))),@$(SCRIPT_DIR)/download.pl "$(DL_DIR)" "$(FILE)" "$(MIRROR_MD5SUM)" || ( $(1) ),$(1))
++	$(if $(if $(MIRROR),$(filter-out x,$(MIRROR_MD5SUM))),@$(SCRIPT_DIR)/download.pl "$(DL_DIR)" "$(FILE)" "$(MIRROR_MD5SUM)" "" || ( $(1) ),$(1))
+ endef
+ 
+ define DownloadMethod/cvs
+@@ -157,6 +157,7 @@ Validate/darcs=VERSION SUBDIR
+ define Download/Defaults
+   URL:=
+   FILE:=
++  URL_FILE:=
+   PROTO:=
+   MD5SUM:=
+   SUBDIR:=
+diff --git a/scripts/download.pl b/scripts/download.pl
+index cd68a7b..111d03c 100755
+--- a/scripts/download.pl
++++ b/scripts/download.pl
+@@ -11,15 +11,19 @@ use warnings;
+ use File::Basename;
+ use File::Copy;
+ 
+-@ARGV > 2 or die "Syntax: $0 <target dir> <filename> <md5sum> [<mirror> ...]\n";
++@ARGV > 2 or die "Syntax: $0 <target dir> <filename> <md5sum> <url filename> [<mirror> ...]\n";
+ 
++my $url_filename;
+ my $target = shift @ARGV;
+ my $filename = shift @ARGV;
+ my $md5sum = shift @ARGV;
++$url_filename = shift @ARGV unless $ARGV[0] =~ /:\/\//;
+ my $scriptdir = dirname($0);
+ my @mirrors;
+ my $ok;
+ 
++$url_filename or $url_filename = $filename;
++
+ sub localmirrors {
+ 	my @mlist;
+ 	open LM, "$scriptdir/localmirrors" and do {
+@@ -106,7 +110,7 @@ sub download
+ 			return;
+ 		}
+ 	} else {
+-		open WGET, "wget -t5 --timeout=20 --no-check-certificate $options -O- '$mirror/$filename' |" or die "Cannot launch wget.\n";
++		open WGET, "wget -t5 --timeout=20 --no-check-certificate $options -O- '$mirror/$url_filename' |" or die "Cannot launch wget.\n";
+ 		open MD5SUM, "| $md5cmd > '$target/$filename.md5sum'" or die "Cannot launch md5sum.\n";
+ 		open OUTPUT, "> $target/$filename.dl" or die "Cannot create file $target/$filename.dl: $!\n";
+ 		my $buffer;