[...] refactor stand-alone build definitions in android/build.gradle (generated artifact)

[brody4hire]

What

• define Android build tools classpath constant, near the beginning of generated android/build.gradle
• rename the new constant in a FIX-UP commit TO BE SQUASHED before or when merging
• add TEMPORARY logging statements for testing purposes only
• explicitly define isStandalone in the beginning of generated android/build.gradle

in followup to updates from PRs #135, #140, and #141

Status

Attempt to build and run example on Android fails with the following output:

Build file '/Users/brodybits/dev/create-react-native-module/cc-788F9A47-CA77-4C23-8CDD-D9561C063828/react-native-bbb/example/node_modules/react-native-bbb/android/build.gradle' line: 17

* What went wrong:
A problem occurred evaluating project ':react-native-bbb'.
> Could not get unknown property 'isStandalone' for object of type org.gradle.api.internal.initialization.DefaultScriptHandler.

If I would test at 636cec6, with the TEMPORARY logging statements but no explicit definition of isStandalone, the following log output is interesting:

> Configure project :react-native-aaa
** starting buildscript for stand-alone
** defining STANDALONE_BUILD_TOOLS_CLASSPATH

This output indicates to me that the buildscript block with the stand-alone build support is executed before any of the initial def items.

At this time I do not understand this. Any help would be much appreciated.

TODO items

• resolve the issue described above, so that it may be possible to define the standalone items in the beginning as proposed here
• remove the TEMPORARY logging statements
• update the tests
• squash down to 1 or 2 commits before or during the merge

/cc @friederbluemle @SaeedZhiany