Create config_setting per apex_name

These are created by bp2build in /build/bazel/rules/apex. Eventually
these config_settings should likely be colocated with the source apex
definition.

Another alternative was to make Bazel's apex a macro that generates a
config_setting. I did not pursue this further for now since it requires the
apex_available of every allowlisted cc_library to also be allowlisted.
This might not always be true (e.g. com.android.runtime)

Test: go test ./bp2build
Change-Id: Ibbb14b0d9c1491b3c79b7634a18d9d35b03922c1

bp2build/cc_library_conversion_test.go

@@ -4454,3 +4454,32 @@ cc_library {
 		},
 	})
 }
+
+// Test that a config_setting specific to an apex is created by cc_library.
+func TestCcLibraryCreatesInApexConfigSetting(t *testing.T) {
+	runCcLibraryTestCase(t, Bp2buildTestCase{
+		Description:                "cc_library creates a config_setting for each apex in apex_available",
+		ModuleTypeUnderTest:        "cc_library",
+		ModuleTypeUnderTestFactory: cc.LibraryFactory,
+		Dir:                        "build/bazel/rules/apex",
+		Blueprint: `
+cc_library {
+	name: "foo",
+	apex_available: [
+	"//apex_available:platform", // This will be skipped, since it is equivalent to //build/bazel/rules/apex:android-non_apex
+	"myapex"
+	],
+}`,
+		ExpectedBazelTargets: []string{
+			MakeBazelTargetNoRestrictions(
+				"config_setting",
+				"android-in_myapex",
+				AttrNameToString{
+					"flag_values": `{
+        "//build/bazel/rules/apex:apex_name": "myapex",
+    }`,
+				},
+			),
+		},
+	})
+}