Kernel build woes

[Gary Thomas <gary@mlbassoc.com>]

Since the recent changes in how the kernel is built, some useful
workflows have been broken.  In particular when working on a
kernel, I use this sequence quite a lot:
   $ bitbake virtual/kernel
   $ bitbake virtual/kernel -c devshell
   ... make some tweaks, add a test patch, etc
   $ bitbake virtual/kernel -C compile

Trying this with a quite recent master (4e20211090d2b193250edaa64f84e355a1c31fe5)
I get this error on the compile step:

ERROR: Function failed: do_compile (log file is located at 
/home/local/qemuarm_2015-01-09/tmp/work/qemuarm-poky-linux-gnueabi/linux-yocto/3.14.24+gitAUTOINC+a227f20eff_6166316d47-r0/temp/log.do_compile.29205)
ERROR: Logfile of failure stored in: 
/home/local/qemuarm_2015-01-09/tmp/work/qemuarm-poky-linux-gnueabi/linux-yocto/3.14.24+gitAUTOINC+a227f20eff_6166316d47-r0/temp/log.do_compile.29205
Log data follows:
| DEBUG: Executing shell function do_compile
| NOTE: make -j 4 zImage CC=arm-poky-linux-gnueabi-gcc  -mno-thumb-interwork -marm LD=arm-poky-linux-gnueabi-ld.bfd
|   CHK     include/config/kernel.release
|   Using /home/local/qemuarm_2015-01-09/tmp/sysroots/qemuarm/usr/src/kernel as source for kernel
|   /home/local/qemuarm_2015-01-09/tmp/sysroots/qemuarm/usr/src/kernel is not clean, please run 'make mrproper'
|   in the '/home/local/qemuarm_2015-01-09/tmp/sysroots/qemuarm/usr/src/kernel' directory.
| make[2]: *** [prepare3] Error 1
| make[1]: *** [sub-make] Error 2
| make: *** [all] Error 2
| ERROR: oe_runmake failed
| WARNING: /home/local/qemuarm_2015-01-09/tmp/work/qemuarm-poky-linux-gnueabi/linux-yocto/3.14.24+gitAUTOINC+a227f20eff_6166316d47-r0/temp/run.do_compile.29205:1 exit 1 from
|   exit 1
| ERROR: Function failed: do_compile (log file is located at 
/home/local/qemuarm_2015-01-09/tmp/work/qemuarm-poky-linux-gnueabi/linux-yocto/3.14.24+gitAUTOINC+a227f20eff_6166316d47-r0/temp/log.do_compile.29205)
ERROR: Task 10 (/home/local/poky-cutting-edge/meta/recipes-kernel/linux/linux-yocto_3.14.bb, do_compile) failed with exit code '1'

Note: this is not unique to the linux-yocto recipe, I've seen
the same error when using some kernel recipes from meta-fsl-arm*,
e.g. linux-boundary, as well as some local recipes which inherit
kernel.bbclass

Should I file this as a bug?

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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