sstate.bbclass: remove previous version's stamp

There is a potential problem if we don't remove the previous version's
stamp, for example:

The depend chain is:
libtool-native -> autoconf-native -> m4-native
We have two m4-native: 1.4.9 and 1.4.7

1) Clean all of them to make a fresh build so that we can reproduce the
   problem
$ bitbake m4-native autoconf-native libtool-native -ccleansstate

2) Build libtool-native so that the m4-native_1.4.17 will be built
$ bitbake libtool-native

3) Set PREFERRED_VERSION_m4-native = "1.4.9" and build again
$ bitbake libtool-native

4) Set PREFERRED_VERSION_m4-native = "1.4.17" and build again
$ bitbake libtool-native -ccleansstate && bitbake libtool-native

Then the build will fail:
[snip]
| m4: unrecognized option '--gnu'
| Try `m4 --help' for more information.
| autom4te: m4 failed with exit status: 1
[snip]

The is because when we change m4-native to 1.4.17 and build
libtool-native again:
5) libtool-native depends on autoconf-native, and autoconf-native's
   version isn't change, so it can remove the current stamp and mirror
   the sstate (the one depends on m4-native_1.4.9) from the SSTATE_DIR
   correctly.

6) The mirrored autoconf-native depends on m4-native_1.4.17's
   do_populate_sysroot, and the stamp is already there (which is made
   by step 2), so it would do nothing, but this is incorrect, since
   the one that really in the sysroot is m4-native_1.4.9, then the
   error happens.

Remove previous version's stamp in sstate_clean() will fix the problem.

[YOCTO #5422]

(From OE-Core rev: 4659d29b1040349116549644e45035a5b37d9311)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions