Update logic protecting lookup of syslinux's source in tools/boot/wheezy/boot-x86

Steve pointed out that this lookup is only here so that helper scripts
can grab those sources and make them available in a public location
such as http://cdimage.debian.org/cdimage/cd-sources/. The sources are
not embedded in the generated ISO and are thus not strictly needed
for building the ISO image.

This should happen even when we're not building source ISOs but it's
not needed if we don't have any similar policy in place. Thus CONF.sh
is now leaving $ARCHIVE_EXTRACTED_SOURCES unset by default and the
source will only be looked up if that value is set.

CONF.sh

@@ -253,8 +253,9 @@ export IMAGESUMS=1
 # We may have to extract files from packages to put them onto the CD
 # (e.g. bootloader files). If you make those packages (and their
 # sources) available somewhere, list it here so that README.source
-# can point to it
-export ARCHIVE_EXTRACTED_SOURCES="http://cdimage.debian.org/cdimage/cd-sources/"
+# can point to it. Note that your mirror must have repositories of
+# source packages if you enable this option.
+# export ARCHIVE_EXTRACTED_SOURCES="http://cdimage.debian.org/cdimage/cd-sources/"
 
 # Produce iso/jigdo files: specify how many iso/jigdo files should be
 # produced in your set. If not set or when the value is "ALL" they will

debian/changelog

@@ -30,7 +30,9 @@ debian-cd (3.1.12) UNRELEASED; urgency=low
     images for i386/amd64. Otherwise a build that doesn't set MKISOFS
     and MKISOFS_OPTS fails.
   * Update tools/boot/wheezy/boot-x86 to not look for syslinux's source
-    package if we're not including sources.
+    if $ARCHIVE_EXTRACTED_SOURCES is not set and modify CONF.sh
+    to not set it by default. That option is only meaningful for
+    official builds that result in a copy of the sources on the given URL.
   * Add dosfstools to Recommends since it's required by
     tools/boot/wheezy/boot-x86 for EFI support. It can't be added to Depends
     because it's not available on non-Linux systems.

tools/boot/wheezy/boot-x86

@@ -197,12 +197,10 @@ fi
 (dpkg --fsys-tarfile "$MIRROR/$SYSLINUXDEB" | \
 	tar xf - -C $CDDIR/../syslinux ./usr/lib)
 
-echo $SYSLINUXDEB >> $CDDIR/../$N.pkgs_extracted
-case $ARCHES in
-    *source*)
+if [ -n "$ARCHIVE_EXTRACTED_SOURCES" ]; then
+	echo $SYSLINUXDEB >> $CDDIR/../$N.pkgs_extracted
 	find_pkg_file syslinux source >> $CDDIR/../$N.pkgs_extracted
-    ;;
-esac
+fi
 
 add_mkisofs_opt $CDDIR/../$N.mkisofs_opts "-isohybrid-mbr syslinux/usr/lib/syslinux/isohdpfx.bin"