Supported python build in host side.

The base module handles all the common functionalites, such as version
compatibilty check, version variations split, source file format check,
source/data file duplicate check.

The library/binary module focuses on how to generate binary build actions,
such as setting up stub script, zipping, filling in __init__.py in
runfiles dir tree.

Bug: b/31676493
Test: go test under python package

Change-Id: I06608369f350f7195873d459e1c8d1bdb811e77e
diff --git a/android/androidmk.go b/android/androidmk.go
index af6608f..b81cc2a 100644
--- a/android/androidmk.go
+++ b/android/androidmk.go
@@ -217,13 +217,22 @@
 	host := false
 	switch amod.Os().Class {
 	case Host:
-		fmt.Fprintln(w, "LOCAL_MODULE_HOST_ARCH :=", archStr)
+		// Make cannot identify LOCAL_MODULE_HOST_ARCH:= common.
+		if archStr != "common" {
+			fmt.Fprintln(w, "LOCAL_MODULE_HOST_ARCH :=", archStr)
+		}
 		host = true
 	case HostCross:
-		fmt.Fprintln(w, "LOCAL_MODULE_HOST_CROSS_ARCH :=", archStr)
+		// Make cannot identify LOCAL_MODULE_HOST_CROSS_ARCH:= common.
+		if archStr != "common" {
+			fmt.Fprintln(w, "LOCAL_MODULE_HOST_CROSS_ARCH :=", archStr)
+		}
 		host = true
 	case Device:
-		fmt.Fprintln(w, "LOCAL_MODULE_TARGET_ARCH :=", archStr)
+		// Make cannot identify LOCAL_MODULE_TARGET_ARCH:= common.
+		if archStr != "common" {
+			fmt.Fprintln(w, "LOCAL_MODULE_TARGET_ARCH :=", archStr)
+		}
 
 		if len(amod.commonProperties.Logtags) > 0 {
 			fmt.Fprintln(w, "LOCAL_LOGTAGS_FILES := ", strings.Join(amod.commonProperties.Logtags, " "))