Support multiple sources for prebuilt_etc

Keep the Src attribute for compatibility. The new attribute (Srcs) is
mutually exclusive with Src.

Keep SourceFilePath and OutputFile for compatibility with other modules.
These can be removed in a follow up change.

Bug: 328313691
Test: presubmit
Test: m blueprint_tests
Test: prebuilts/build-tools/build-prebuilts.sh (on build-tools branch)
Change-Id: I5d5b2657715a7180a829c7ed0f501872d561b662
diff --git a/etc/prebuilt_etc_test.go b/etc/prebuilt_etc_test.go
index df11709..1d9aa8e 100644
--- a/etc/prebuilt_etc_test.go
+++ b/etc/prebuilt_etc_test.go
@@ -96,7 +96,7 @@
 	`)
 
 	p := result.Module("foo.conf", "android_arm64_armv8-a").(*PrebuiltEtc)
-	android.AssertStringEquals(t, "output file path", "foo.installed.conf", p.outputFilePath.Base())
+	android.AssertStringEquals(t, "output file path", "foo.installed.conf", p.outputFilePaths[0].Base())
 }
 
 func TestPrebuiltEtcGlob(t *testing.T) {
@@ -113,10 +113,24 @@
 	`)
 
 	p := result.Module("my_foo", "android_arm64_armv8-a").(*PrebuiltEtc)
-	android.AssertStringEquals(t, "my_foo output file path", "my_foo", p.outputFilePath.Base())
+	android.AssertStringEquals(t, "my_foo output file path", "my_foo", p.outputFilePaths[0].Base())
 
 	p = result.Module("my_bar", "android_arm64_armv8-a").(*PrebuiltEtc)
-	android.AssertStringEquals(t, "my_bar output file path", "bar.conf", p.outputFilePath.Base())
+	android.AssertStringEquals(t, "my_bar output file path", "bar.conf", p.outputFilePaths[0].Base())
+}
+
+func TestPrebuiltEtcMultipleSrcs(t *testing.T) {
+	result := prepareForPrebuiltEtcTest.RunTestWithBp(t, `
+		prebuilt_etc {
+			name: "foo",
+			srcs: ["*.conf"],
+		}
+	`)
+
+	p := result.Module("foo", "android_arm64_armv8-a").(*PrebuiltEtc)
+	android.AssertStringEquals(t, "output file path", "bar.conf", p.outputFilePaths[0].Base())
+	android.AssertStringEquals(t, "output file path", "baz.conf", p.outputFilePaths[1].Base())
+	android.AssertStringEquals(t, "output file path", "foo.conf", p.outputFilePaths[2].Base())
 }
 
 func TestPrebuiltEtcAndroidMk(t *testing.T) {