We can only change the TMPDIR if we want to change the STAMP's location,
but the bb_cache.dat would be regenerated if TMPDIR changes, so add
STAMPS_DIR for constructing it, and add it to the BB_ENV_EXTRAWHITE,
this is very usefull for the "bitbake -S", since then it can be run by:
STAMPS_DIR=<path> bitbake -S <recipe>
which will avoid putting the stamps to ${TMPDIR}/stamps.
BTW, break the too long BB_ENV_EXTRAWHITE into several lines.
[YOCTO #1659]
Signed-off-by: Robert Yang <liezhi.yang@windriver.com> Signed-off-by: Saul Wold <sgw@linux.intel.com>