Port for Android Build/Mac environment

* Add Android.bp
* Add required header files for Mac env

Test: android master build on marlin, partners build
Change-Id: Iab4120add93750faf32be3cdf7a04adf30ea93e3
diff --git a/libkmod/libkmod-index.c b/libkmod/libkmod-index.c
index 1f3351a..05669dc 100644
--- a/libkmod/libkmod-index.c
+++ b/libkmod/libkmod-index.c
@@ -692,7 +692,7 @@
 		for (i = 0; i < child_count; i++)
 			children[i] = read_long_mm(&p);
 	} else {
-		first = INDEX_CHILDMAX;
+		first = (char)INDEX_CHILDMAX;
 		last = 0;
 		child_count = 0;
 	}