cpansearch: depend on `pcre` on macOS.
cpansearch: depend on `pcre` on macOS.

The existing macOS bottles have linkage with `pcre`, which is in this
formula's dependency tree through `glib`.

This dependency will be removed in #111019, so that will result in
broken linkage for new installs. Let's avoid that by adding the
appropriate dependency.

This fixes a test failure in #111019.

Closes #111038.

Signed-off-by: BrewTestBot <8a898ee6867e4f2028e63d2a6319b2224641c06c@users.noreply.github.com>

stgraber/homebrew-core,lemzwerg/homebrew-core,stgraber/homebrew-core,Homebrew/homebrew-core,filcab/homebrew-core,nandub/homebrew-core,sjackman/homebrew-core,nandub/homebrew-core,makigumo/homebrew-core,adam-moss/homebrew-core,chrisfinazzo/homebrew-core,sjackman/homebrew-core,chrisfinazzo/homebrew-core,Homebrew/homebrew-core,makigumo/homebrew-core,filcab/homebrew-core,adam-moss/homebrew-core,lemzwerg/homebrew-core