The globs used for STAMPCLEAN were too greedy matching gcc-cross-initial
stamps for gcc-cross for example. This patch resolves that problem making
the assumption that PV starts with something numeric. This assumption
should hold in most cases and has a better failure case that the current
situation.
(From OE-Core rev: d7fbc70b6c6ac629d2a23ac16ab45461f88b4b26)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>