existing jdk, android sdk/ndk, cmake not found

[ToddG]

Looking at code for jdk_helper, for example, it appears that the code to detect existing jdk is not yet implemented.

[halfnelson]

it tries jdk for windows, but other operating systems it doesn't since it will download and use its own.
The jdk stuff could be improved to use existing ones on each os, but jdk 8 might break things etc so I think it is safer to use a known good version for each os. I am happy to accept patches to detect a jdk 1.7 on linux or osx.

NDK and SDK will always use its own known good copy. Maybe I will reactive the config that lets you override the built in ones at your own risk. Will accept patches for this too :)

Thanks again for the feedback.