conf/179422: "make: don't know how to make bsd.README. Stop" error message should be more intuitive when Makefiles are missing

[Garrett Cooper]

>Number:         179422
>Category:       conf
>Synopsis:       "make: don't know how to make bsd.README. Stop" error message should be more intuitive when Makefiles are missing
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Jun 08 02:20:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Garrett Cooper
>Release:        10-CURRENT
>Organization:
EMC Isilon
>Environment:
FreeBSD gran-tourismo.west.isilon.com 10.0-CURRENT FreeBSD 10.0-CURRENT #2 r+ba9afe9: Fri Apr 19 20:29:10 PDT 2013     gcooper at gran-tourismo.west.isilon.com:/usr/obj/usr/src/sys/GRAN-TOURISMO  amd64
>Description:
I forget the exact circumstances for how to reproduce this error, but basically if you either are missing a Makefile in a subdirectory and gets cd'ed to in Makefile.inc1, or via bsd.subdir.mk, you'll run into this problem, and it's not very intuitive:

make: don't know how to make bsd.README. Stop

Having a more intuitive error message, or checking for Makefile would be nice. Please note that this issue might be resolved via my proposed changes for conf/179111 .
>How-To-Repeat:
- cd usr.bin
- echo 'SUBDIR+= doesnotexist' >> Makefile
- make obj
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: