lib.sh: introduce mandatory check of projectname

error out if it's not set. ditto projectsite.

that way, if the files are accidentally deleted, or not
added in a derivative of the build system, you'll know.

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

include/lib.sh

@@ -45,6 +45,7 @@ eval `setvars "" tmpdir _nogit board boarddir relname versiondate projectsite \
 for fv in projectname projectsite version versiondate; do
 	eval "[ ! -f "$fv" ] || read -r $fv < \"$fv\" || :"
 done
+chkvars projectname projectsite
 
 setcfg()
 {