Refine Carthage instructions.

// FREEBIE

BUILDING.md

@@ -17,11 +17,15 @@ occasionally, CocoaPods itself will need to be updated. Do this with
 sudo gem update
 ```
 
-3) Some dependencies are added via carthage. Run:
+3) Some dependencies are added via carthage. However, our prebuilt WebRTC.framework also resides in the Carthage directory. 
+
+Run:
 ```
-carthage checkout
+// DO NOT run: `carthage update` or `carthage checkout`.
+git submodule update --init
 carthage build
 ```
+
 If you don't have carthage, here are install instructions:
 ```
 https://github.com/Carthage/Carthage#installing-carthage
@@ -46,4 +50,29 @@ value to "build".
 
 Features related to push notifications are known to be not working for third-party contributors since Apple's Push Notification service pushs will only work with Open Whisper Systems production code signing certificate.
 
+### Building WebRTC
+
+A prebuilt version of WebRTC.framework resides in our Carthage submodule (see above).
+However, if you'd like to build it from souce, this is how it's done.
+
+These instructions are derived from the WebRTC documentation:
+
+https://webrtc.org/native-code/ios/
+
+    # 1. Install depot tools
+    cd <somewhere>
+    git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
+    cd depot_tools
+    export PATH=<somewhere>/depot_tools:"$PATH"
+    # 2. Fetch webrtc source
+    cd <somewhere else>
+    mkdir webrtc
+    cd webrtc
+    fetch --nohooks webrtc_ios
+    gclient sync
+    # 3. Build webrtc
+    cd src
+    webrtc/build/ios/build_ios_libs.sh
+	# 4. Move the WebRTC.framework into Signal-iOS's Carthage directory
+    mv out_ios_libs/WebRTC.framework <Your Signal-iOS repository>/Carthage/Build/iOS/
 

MAINTAINING.md

@@ -9,34 +9,9 @@ Keeping cocoapods based dependencies is easy enough.
 
 `pod update`
 
-### WebRTC
-
-We don't currently have an automated build (cocoapod/carthage) setup for
-the WebRTC.framework. Instead, read the WebRTC upstream source and build
-setup instructions here:
-
-https://webrtc.org/native-code/ios/
-
-Once you have your build environment set up and the WebRTC source downloaded:
-
-    # The specific set of commands that worked for me were somewhat different.
-    # 1. Install depot tools
-    cd <somewhere>
-    git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
-    cd depot_tools
-    export PATH=<somewhere>/depot_tools:"$PATH"
-    # 2. Fetch webrtc source
-    cd <somewhere else>
-    mkdir webrtc
-    cd webrtc
-    fetch --nohooks webrtc_ios
-    gclient sync
-    # 3. Build webrtc
-    # NOTE: build_ios_libs.sh only worked for me from inside "src"
-    cd src
-    webrtc/build/ios/build_ios_libs.sh
-    # NOTE: It's Carthage/Build/iOS, not Carthage/Builds
-    mv out_ios_libs/WebRTC.framework ../../Signal-iOS/Carthage/Build/iOS/
+Similarly, Carthage dependencies can be updated like so:
+
+`carthage update`
 
 ## Translations