lib.sh: more unified config handling

replace it with logic that simply uses "." to load
files directly. for this, "vcfg" is added as a variable
in coreboot target.cfg files, referring to a directory
in config/vendor/ containing a file named pkg.cfg, and
this file then contains the same variables as the
erstwhile config/vendor/sources

config/git files are now directories, also containing
pkg.cfg files each with the same variables as before,
such as repository link and commit hash

this change results in a noticeable reduction in code
complexity within the build system.

unified reading of config files: new function setcfg()
added to lib.sh

setcfg checks if a config exists. if a 2nd argument is
passed, it is used as a return value for eval, otherwise
a string calling err is passed. setcfg output is passed
through eval, to set strings based on config; eval must
be used, so that the variables are set within the same
scope, otherwise they'd be set within setcfg which could
lead to some whacky results.

there's still a bit more more to do, but this single change
results in a substantial reduction in code complexity.

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

include/git.sh

@@ -31,10 +31,8 @@ fetch_config()
 
 load_target_config()
 {
-	[ -f "$cfgsdir/$1/target.cfg" ] || $err "$1: target.cfg missing"
 	[ -f "$cfgsdir/$1/seen" ] && $err "$_xm cfg: infinite loop in trees"
-
-	. "$cfgsdir/$1/target.cfg" || $err "load_target_config !$cfgsdir/$1"
+	eval `setcfg "$cfgsdir/$1/target.cfg"`
 	touch "$cfgsdir/$1/seen" || $err "load_config $cfgsdir/$1: !mk seen"
 }
 
@@ -50,9 +48,9 @@ prepare_new_tree()
 fetch_project_repo()
 {
 	eval "$(setvars "" xtree tree_depend)"
+	eval `setcfg "config/git/$project/pkg.cfg"`
 
-	scan_config "$project" "config/git"
-	chkvars loc url
+	chkvars url
 
 	[ -n "$xtree" ] && [ ! -d "src/coreboot/$xtree" ] && \
 		x_ ./update trees -f coreboot "$xtree"
@@ -63,14 +61,14 @@ fetch_project_repo()
 	clone_project
 
 	for x in config/git/*; do
-		[ -f "$x" ] && nuke "${x##*/}" "src/${x##*/}" 2>/dev/null
-	done
+		[ -d "$x" ] && nuke "${x##*/}" "src/${x##*/}" 2>/dev/null
+	done; return 0
 }
 
 clone_project()
 {
-	loc="${loc#src/}"
-	loc="src/$loc"
+	loc="src/$project"
+	singletree "$project" || loc="src/$project/$project"
 
 	printf "Downloading project '%s' to '%s'\n" "$project" "$loc"
 	e "$loc" d && return 0