Update Prerequisites for cross-compiling

Signed-off-by: Huy Duong <[email protected]>

README.md

@@ -2,10 +2,19 @@
 Android's adb ported to ARM with automake source structures
 
 ## Prerequisites
+NOTE: Please make sure you are using navite/cross gcc >= 4.9
 ```bash
 $ sudo apt-get install libtool automake
 ```
-NOTE: Please make sure you are using navite/cross gcc >= 4.9
+For cross-compiling:
+### ARM
+```bash
+$ sudo apt-get install linux-libc-dev-armhf-cross libc6-armhf-cross libc6-dev-armhf-cross
+```
+### AARCH64
+```bash
+$ sudo apt-get install linux-libc-dev-arm64-cross libc6-arm64-cross libc6-dev-arm64-cross
+```
 
 ## How to build and run
 ### Native compiling