tree 8f53e4e58165fc2c7f62e17b31dfb77ef43d7dfc
parent 12715d20af9fd9179daca7a1cd2cf3db3c2c494f
author Sam Ravnborg <sam@mars.ravnborg.org> 1155065714 +0200
committer Sam Ravnborg <sam@neptun.ravnborg.org> 1159167709 +0200

kbuild: make V=2 tell why a target is rebuild

tell why a a target got build
   enabled by make V=2
      Output (listed in the order they are checked):
         (1) - due to target is PHONY
         (2) - due to target missing
         (3) - due to: file1.h file2.h
         (4) - due to command line change
         (5) - due to missing .cmd file
         (6) - due to target not in $(targets)
(1) We always build PHONY targets
(2) No target, so we better build it
(3) Prerequisite is newer than target
(4) The command line stored in the file named dir/.target.cmd
    differed from actual command line. This happens when compiler
    options changes
(5) No dir/.target.cmd file (used to store command line)
(6) No dir/.target.cmd file and target not listed in $(targets)
    This is a good hint that there is a bug in the kbuild file

This patch is inspired by a patch from: Milton Miller <miltonm@bga.com>

Cc: Milton Miller <miltonm@bga.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>