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>

script/roms

@@ -91,10 +91,9 @@ configure_target()
 	board="$1"
 
 	targetdir="$cfgsdir/$board"
-	[ -f "$targetdir/target.cfg" ] || $err "$board: target.cfg missing"
 
 	# Override the above defaults using target.cfg
-	. "$targetdir/target.cfg"
+	eval `setcfg "$targetdir/target.cfg"`
 
 	[ -z "$grub_scan_disk" ] && grub_scan_disk="nvme ahci ata"
 

script/trees

@@ -35,7 +35,7 @@ main()
 	[ -z "$_f" ] && $err "missing flag (-m/-u/-b/-c/-x/-f/-s/-l/-n)"
 	[ -z "$project" ] && $err "project name not specified"
 
-	[ -f "config/git/$project" ] || $err "project '$project' not defined"
+	[ -f "config/git/$project/pkg.cfg" ] || $err "'$project' not defined"
 
 	elfdir="elf/$project"
 	datadir="config/data/$project"
@@ -154,9 +154,7 @@ load_project_config()
 {
 	eval "$(setvars "" xarch xlang tree bootstrapargs autoconfargs xtree \
 	    tree_depend makeargs)"
-
-	[ -f "$1/target.cfg" ] || return 0
-	. "$1/target.cfg" || $err "loadp $1: can't load target.cfg"; return 0
+	eval `setcfg "$1/target.cfg" 0`; return 0
 }
 
 check_cross_compiler()
@@ -274,15 +272,12 @@ check_makefile()
 
 mkpayload_grub()
 {
-	[ -f "$grubdata/module/$tree" ] || $err "$tree: grub modules missing"
-	x_ rm -f "$cdir/grub.elf"
-
 	eval "$(setvars "" grub_modules grub_install_modules)"
-
-	. "$grubdata/module/$tree" || $err "$tree: !source grub modules"
-
+	eval `setcfg "$grubdata/module/$tree"`
 	chkvars "grub_install_modules" "grub_modules"
 
+	x_ rm -f "$cdir/grub.elf"
+
 	"${cdir}/grub-mkstandalone" --grub-mkimage="${cdir}/grub-mkimage" \
 	    -O i386-coreboot -o "${cdir}/grub.elf" -d "${cdir}/grub-core/" \
 	    --fonts= --themes= --locales=  --modules="$grub_modules" \
@@ -290,7 +285,7 @@ mkpayload_grub()
 	    "/boot/grub/grub_default.cfg=${cdir}/.config" \
 	    "/boot/grub/grub.cfg=$grubdata/memdisk.cfg" \
 	    "/background.png=$grubdata/background/background1280x800.png" || \
-	    $err "$tree: cannot build grub.elf"
+	    $err "$tree: cannot build grub.elf"; return 0
 }
 
 copy_elf()