Add optional output_filename argument in rootfs.sh

Downloads to a particular filename, allows for different names than
whatever is upstream.

rootfs.sh

@@ -27,22 +27,17 @@ sudo mount -t tmpfs -o size=8G tmpfs tmp
 
 LOGFILE="$PWD/tmp/bootstrap.log"
 
-wget()
-{
+_wget() {
     local url="$1"
     local dir="${CACHEDIR:-$GITDIR/sources}"
-	local file
-
-	file=$(basename "$url")
+    local file="${2:-$(basename "${url}")}"
     mkdir -p "$dir"
-
     test -s "$dir/$file" || command wget -O "$dir/$file" "$url"
     cp -v "$dir/$file" .
     checksum_do "$dir" "$file"
 }
 
-checksum_do()
-{
+checksum_do() {
     local dir="$1"
     local file="$2"
     local line
@@ -127,11 +122,12 @@ tar -C tmp/after/tar-1.12/src -xf "tmp/after/tar-1.12/src/$(basename $url)" --st
 get_file() {
     url=$1
     make_build=${2:-0}
+    output_filename=$3
     ext="${url##*.}"
     if [ "$ext" = "tar" ]; then
-        bname=$(basename "$url" ".tar")
+        bname=$(basename "${output_filename:-${url}}" ".tar")
     else
-        bname=$(basename "$url" ".tar.${ext}")
+        bname=$(basename "${output_filename:-${url}}" ".tar.${ext}")
     fi
     cp -r "${bname}" tmp/after/
     target="tmp/after/${bname}"
@@ -141,7 +137,7 @@ get_file() {
     fi
     pushd "tmp/after/${bname}/src"
     if [ ! -f "$(basename "$url")" ]; then
-        wget "$url"
+        _wget "$url" "${output_filename:-${url##*/}}"
     fi
     popd
 }