databases/pecl-couchbase: fix build on armv7

This port bundles an older version of snappy that does not build on
armv7 due to an issue that was fixed in the snappy port long ago.
Grab my old armv7 patch for archivers/snappy from the attic to fix
the build. Long term, the dependency should probably be unbundled.

See also: 9a0a2422622d5feee7d77ddc954540daff449a1d
Approved by: portmgr (build fix blanket)
MFH: 2026Q2