exim: add subpackages, for lookups, scripts and utils. (#30647)

This PR adds sub-packages that are present in the alpine package
(https://gitlab.alpinelinux.org/alpine/aports/-/blob/master/community/exim/APKBUILD)
that weren't in the Wolfi package. Specifically it adds sub-packages for
lookups (postgres, mysql and others) as well as packaging the
`exim-utils` and `exim-scripts` too.
Additionally, as also present in the alpine package, it adds a
pre-install script to configure the `exim` user upon package
installation.


Fixes:
* #29568

exim.yaml

@@ -1,14 +1,21 @@
 package:
   name: exim
   version: "4.98"
-  epoch: 2
+  epoch: 3
   description: Message Transfer Agent
   copyright:
     - license: GPL-2.0-or-later
   checks:
     disabled:
       - setuidgid
 
+data:
+  - name: exim-lookups-with-deps
+    items:
+      mysql: "mariadb-connector-c"
+      sqlite: "sqlite-libs"
+      pgsql: "libpq"
+
 environment:
   contents:
     packages:
@@ -35,7 +42,7 @@ environment:
   accounts:
     users:
       - username: exim
-        uid: 1001
+        uid: 65332
 
 pipeline:
   - uses: fetch
@@ -74,9 +81,78 @@ pipeline:
   - uses: strip
 
 subpackages:
+  - range: exim-lookups-with-deps
+    name: exim-${{range.key}}
+    description: "EXIM extension: ${{range.key}}"
+    pipeline:
+      - runs: |
+          install -D -m 755 ./build-Linux-${{build.arch}}/lookups/${{range.key}}.so ${{targets.subpkgdir}}/usr/lib/${{package.name}}/${{range.key}}.so
+      - uses: strip
+    dependencies:
+      runtime:
+        - exim=${{package.full-version}}
+        - ${{range.value}}
+
+  - name: exim-dnsdb
+    description: "EXIM extension: dnsdb"
+    pipeline:
+      - runs: |
+          install -D -m 755 ./build-Linux-${{build.arch}}/lookups/dnsdb.so ${{targets.subpkgdir}}/usr/lib/${{package.name}}/dnsdb.so
+      - uses: strip
+    dependencies:
+      runtime:
+        - exim=${{package.full-version}}
+
+  - name: exim-dbmdb
+    description: "EXIM extension: dbmdb"
+    pipeline:
+      - runs: |
+          install -D -m 755 ./build-Linux-${{build.arch}}/lookups/dbmdb.so ${{targets.subpkgdir}}/usr/lib/${{package.name}}/dbmdb.so
+      - uses: strip
+    dependencies:
+      runtime:
+        - exim=${{package.full-version}}
+
+  - name: exim-cdb
+    description: "EXIM extension: cdb"
+    pipeline:
+      - runs: |
+          install -D -m 755 ./build-Linux-${{build.arch}}/lookups/cdb.so ${{targets.subpkgdir}}/usr/lib/${{package.name}}/cdb.so
+
+  - name: exim-scripts
+    description: "EXIM scripts"
+    pipeline:
+      - runs: |
+          make	DESTDIR="${{targets.subpkgdir}}" INSTALL_ARG="exicyclog exim_checkaccess eximstats exiqgrep exigrep exinext exiqsumm exipick exiwhat convert4r3 convert4r4 exim_msgdate exim_id_update" install
+          rm -fr "${{targets.subpkgdir}}/etc"
+      - uses: strip
+    dependencies:
+      runtime:
+        - exim=${{package.full-version}}
+        - perl
+        - perl-file-fcntllock
+
+  - name: exim-utils
+    description: "EXIM utils"
+    pipeline:
+      - runs: |
+          install -d "${{targets.subpkgdir}}/etc/mail"
+          make DESTDIR="${{targets.subpkgdir}}" INSTALL_ARG="exim_dbmbuild exim_dumpdb exim_tidydb exim_fixdb exim_lock" install
+          rm -fr "${{targets.subpkgdir}}/etc"
+      - uses: strip
+    dependencies:
+      runtime:
+        - exim=${{package.full-version}}
 
 test:
   environment:
+    accounts:
+      users:
+        - username: exim
+          uid: 65332
+      groups:
+        - groupname: exim
+          gid: 65332
     contents:
       packages:
         - shadow
@@ -85,7 +161,6 @@ test:
   pipeline:
     - name: "Test exim is installed and working"
       runs: |
-        useradd exim
         if ! command -v exim &> /dev/null; then
           echo "Exim is not installed."
           exit 1