[rajtik76]

Part of flock-php/flock#107

What and why

imap left PHP's core in 8.4 and Flock's PHP doesn't have it, so apps requiring ext-imap can't run on Flock.

• macOS and Linux: imap is added to shared_extensions, so every minor (8.1–8.5) ships ext/imap.so. 8.1–8.3 build the extension in php-src; 8.4+ build PECL imap 1.0.3, pinned in build.sh like opentelemetry. Linked against static-php-cli's c-client with OpenSSL, no Kerberos.
• The 8.4+ tarballs still contain ext/imap/tests, so static-php-cli treats the extension as extracted and skips the PECL source. build.sh extracts php-src first and removes the leftover when it has no config.m4.
• FrankenPHP: static-php-cli refuses imap in ZTS builds (not thread-safe). frankenphp.skip_extensions takes it out of the shared list in both jobs of the macOS and Linux workflows, so build, smoke test and flock-package.json agree.
• Windows: the official builds have php_imap.dll up to 8.3. For 8.4 and 8.5 the packs add the PHP team's PECL DLL from downloads.php.net. Those have no published checksum, so php.windows.extensions.imap pins the SHA-256 per minor.
• build raised for macOS, Linux and the Windows packs to rebuild the published versions.

Flock loads the extension with flock-php/flock#109.

How I tested it

CI on my fork, nothing published: runs

• php 8.1.34, 8.2.35, 8.3.36, 8.4.27, 8.5.12 on macos-arm64, linux-x64 and linux-arm64: build, portability check and smoke test with REQUIRE_SHARED=1, then the fresh runner / no-Homebrew job.
• frankenphp 8.4.27 on macos-arm64 and linux-x64: built without imap, smoke test passes.
• php-exts 8.3, 8.4, 8.5: 8.4 and 8.5 load imap 1.0.3.

Locally, the official imap test suite (php-src ext/imap/tests for 8.1–8.3, PECL 1.0.3's for 8.4+) against Dovecot 2.3 with the suite's own config:

	macOS (this build)	Windows (official build + DLL)
8.1	87/87	87/87
8.2	89/89	89/89
8.3	89/89	89/89
8.4	88/88	88/88
8.5	88/88	88/88

Notes:

• bug63126 is skipped everywhere: it needs a GSSAPI-capable client and server, and none of these builds has Kerberos (upstream skips it on CI too).
• On PHP 8.5, imap_fetchbody_basic fails in the suite itself: it uses case 'FT_UID';, deprecated in 8.5. With : it passes. Not fixed upstream yet.
• The Windows DLL has no CRAM-MD5, so Dovecot also offered PLAIN/LOGIN there.

A Laravel app's imap import tests that failed with Undefined constant "OP_SILENT" pass on the 8.4 and 8.5 macOS builds.