Add mention of static feature in README and macos CI job

.github/workflows/test.yml

@@ -46,3 +46,14 @@ jobs:
       - uses: actions/checkout@v2
       - name: 'Test static-bindgen'
         run: 'make static-bindgen'
+  test-static-linking:
+    runs-on: ${{ matrix.runs-on }}
+    strategy:
+      matrix:
+        runs-on: [ubuntu-latest, macos-latest]
+    steps:
+      - uses: actions/checkout@v2
+      - if: ${{ matrix.runs-on == "macos-latest" }}
+        run: make macos-test
+      - if: ${{ matrix.runs-on == "ubuntu-latest" }}
+        run: make test

Makefile

@@ -73,6 +73,13 @@ docker-test:
 			${DOCKER_REPO}/${DOCKER_TEST_ENV}:${USED_BUILDENV_VERSION}
 .PHONY: docker-test
 
+# Test with the homebrew version of icu4c on macOS with static linking (the default way of linking for distribution on Apple platforms)
+macos-test:
+	brew install icu4c
+	RUST_ICU_LINK_SEARCH_DIR=$(brew --prefix)/opt/icu4c/lib \
+	cargo test --no-default-features --features=icu_version_64_plus,icu_version_67_plus,icu_version_68_plus,icu_version_in_env,renaming,static
+.PHONY: macos-test
+
 # Refreshes the static bindgen output (contents of ./rust_icu_sys/bindgen) based
 # on the currently present ICU versions in the test environment.
 #