xbmk: remove the setcfg function

this allows me to remove several eval calls, and the
errors relating to configs can now show exactly which
function they occured in, allowing for easier debugging.

once again, eval should be used sparingly if at all.

Signed-off-by: Leah Rowe <leah@libreboot.org>

include/tree.sh

@@ -222,7 +222,9 @@ configure_project()
 	# globally initialise all variables for a source tree / target:
 
 	if e "$datadir/mkhelper.cfg" f; then
-		eval "`setcfg "$datadir/mkhelper.cfg"`"
+		. "$datadir/mkhelper.cfg" || \
+		    err "Can't read '$datadir/mkhelper.cfg'" \
+		    "configure_project" "$@"
 	fi
 
 	# override target/tree specific variables from per-target config:
@@ -241,7 +243,8 @@ configure_project()
 		rev=""
 		tree=""
 
-		eval "`setcfg "$_tcfg"`"
+		. "$_tcfg" || \
+		    err "Can't read '$_tcfg'" "configure_project" "$@"
 
 		if [ "$_f" = "-d" ]; then
 			build_depend="" # dry run