[OE-core] [PATCH] autotools.bbclass: Add functionality to force a clean of ${B} when reconfiguring (and ${S} != ${B})

[Phil Blundell]

On Tue, 2012-09-11 at 15:22 +0100, Richard Purdie wrote:
> Unfortunately whilst rerunning configure and make against a project will mostly
> work there are situations where it does not correctly do the right thing.
> 
> In particular, eglibc and gcc will fail out with errors where settings
> do not match a previously built configuration. It could be argued they are
> broken but the situation is what it is. There is the possibility of more subtle
> errors too.

FWIW, I just encountered another instance of what appears to be a
similar problem (with this patch applied).  I had changed my CFLAGS to
work around a compiler problem and then just reran the build, which led
eventually to:

ERROR: Function failed: do_siteconfig_gencache
(see ..../tmp-eglibc/work/mips32el-oe-linux/eglibc/2.16-r11.micro1
+svnr20393/temp/log.do_populate_sysroot.6005 for further information)
ERROR: Logfile of failure stored
in: ..../tmp-eglibc/work/mips32el-oe-linux/eglibc/2.16-r11.micro1
+svnr20393/temp/log.do_populate_sysroot.6005
Log data follows:
| DEBUG: Executing python function sstate_task_prefunc
[...]
| DEBUG: Executing shell function do_siteconfig_gencache
| configure: WARNING: unrecognized options: --disable-silent-rules,
--disable-dependency-tracking, --with-libtool-sysroot
| configure: loading cache eglibc_cache
| configure: error: `CFLAGS' has changed since the previous run:
| configure:   former value:  `...'
| configure:   current value: `...'
| configure: error: in
`/.../tmp-eglibc/work/mips32el-oe-linux/eglibc/2.16-r11.micro1
+svnr20393/site_config_cheetah':
| configure: error: changes in the environment can compromise the build
| configure: error: run `make distclean' and/or `rm eglibc_cache' and
start over
| DEBUG: Python function siteconfig_do_siteconfig finished
| DEBUG: Python function autotools_do_siteconfig finished
| DEBUG: Python function do_siteconfig finished
| DEBUG: Python function sstate_task_postfunc finished
ERROR: Task 30 (.../oe-core/meta/recipes-core/eglibc/eglibc_2.16.bb,
do_populate_sysroot) failed with exit code '1'

p.