Update README, add .md extension

README → README.md

+# Ring Android
+
+## Environnement
+
 Make sure you have the android-ndk and android-sdk, and you'll want something
 like this in your .bashrc (or equivalent):
 
-# setup Android paths
 export ANDROID_NDK=$HOME/src/android-ndk
 export ANDROID_NDK_ROOT=$ANDROID_NDK
 export ANDROID_SDK=$HOME/src/android-sdk-linux
@@ -9,9 +12,21 @@ export ANDROID_HOME=$ANDROID_SDK
 export PATH=$ANDROID_SDK/platform-tools:${PATH}
 
 
+## Build instructions
+
 When all else fails:
 
 rm -rf sflphone
 git clean -dfx
 export ANDROID_ABI=armeabi-v7a
 ./compile.sh
+
+
+## Common issues
+
+* Makeinfo issue
+
+    makeinfo: command not found
+    WARNING: 'makeinfo' is missing on your system.
+
+    **Solution**: Install texinfo package containing makeinfo dep.