A lot of text here, trying to be thorough..
So checking off the requirements:
For compiling under Windows, Linux or OSX, the following is required:
• Python 2.7+ (3.0 is untested as of now).
Python 2.7.11 (v2.7.11:6d1b6a68f775, Dec 5 2015, 20:32:19) [MSC v.1500 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information.
• SCons build system.
scons: Reading SConscript files ...
No valid target platform selected.
The following were detected:
• Android SDK version 19 [Note: Please install all Tools and Extras of sdk manager]
• Android build tools version 19.1
The SDK Manager says I have SDK Tools 26.1.6, SDK Platform-tools 23.1 and SDK Build-tools 19.1 (and others). Is that ok?
• Android NDK
I have r10e installed (see path below). I also set ANDROID_HOME
Well, I installed it and set GRADLE_HOME. Then I did the 12.5.6 Building the APK command, gradlew.bat buid. After downloading a lot of stuff (including another version of Gradle?) I got this
FAILURE: Build failed with an exception.
* What went wrong:
A problem occurred configuring root project 'java'.
> failed to find target android-19 : H:\Android
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
Total time: 3 mins 16.54 secs
EDIT: Update to the above--I got success with this step after I found ANDROID_HOME was incorrect. But other steps still fail
• OpenJDK 6 or later (or Oracle JDK 6 or later)
java -version reports:
java version "1.8.0_92"
Java(TM) SE Runtime Environment (build 1.8.0_92-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.92-b14, mixed mode)
Set the environment variable ANDROID_HOME to point to the Android SDK.
Set the environment variable ANDROID_NDK_ROOT to point to the Android NDK.