macos CI: explicitly install gettext

We need msgfmt for embedding translations.

Part of #11828

.github/workflows/main.yml

@@ -163,7 +163,7 @@ jobs:
         # --break-system-packages because homebrew has now declared itself "externally managed".
         # this is CI so we don't actually care.
         sudo pip3 install --break-system-packages pexpect
-        brew install tmux
+        brew install gettext tmux
     - name: cmake
       run: |
         mkdir build && cd build

.github/workflows/release.yml

@@ -150,6 +150,8 @@ jobs:
         uses: ./.github/actions/rust-toolchain@stable
         with:
           targets: aarch64-apple-darwin
+      - name: Install dependencies
+        run: brew install gettext
       - name: Build and codesign
         run: |
           die() { echo >&2 "$*"; exit 1; }