Stop cmake warning that we are using an internal target name.

* CMakeLists.txt: Rename "test" to "tests"

* Makefile.in: Chase target name, add a compatibility target for the old
  name.

CMakeLists.txt

@@ -151,9 +151,9 @@ include(GlibCompileResourcesSupport)
 # Unit tests.
 #
 # We don't use CMake's enable_testing/add_test built-ins because they
-# use ctest.
-add_custom_target(test ALL geary-test)
-add_dependencies(test geary-test)
+# use ctest. It's not called "test" because that is cmake reserved.
+add_custom_target(tests ALL geary-test)
+add_dependencies(tests geary-test)
 
 #
 # Uninstall target

Makefile.in

@@ -37,12 +37,16 @@ distclean: clean
 	@-rm -rf $(BUILD_DIR)
 	@-rm -f Makefile
 
-.PHONY: test
-test:
+.PHONY: tests
+tests:
 	@$(MAKE) -C $(BUILD_DIR) $@
 
+.PHONY: test
+test:
+	@$(MAKE) -C $(BUILD_DIR) tests
+
 .PHONY: dist
-dist: test
+dist: tests
 	@$(MAKE) -C $(BUILD_DIR) dist
 	@cp build/*.xz .