lang/php81: Update version 8.1.7=>8.1.8

• Add STRIP_CMD for some binaries and libs [1]

Reported by: sunpoet [1]
Relnotes: https://www.php.net/ChangeLog-8.php#8.1.8
Sponsored by: Bounce Experts

(cherry picked from commit 0f0109c551ad0a25a952c92d3b0815c29a4f23cc)