This commit updates the "browser-asmjs" images to avoid systematic
rebuild of emscripten sdk. Instead, it introduces dependency on the
image maintained by @trzeci
Note also:
* emscripten sdk updated from 1.36.7 to 1.36.14
* symlinking of "/bin/bash" as "/bin/sh" is reverted. This ensures other
images including file like "common.debian" and relying on standard "sh"
behavior will work as expected.
* workaround associated with CMakeForceCompiler has been removed from
Dockerfile. Emscripten as been fixed.
See https://github.com/kripken/emscripten/pull/4477
* we will revisit once official images are available.
See https://github.com/kripken/emscripten/issues/4682
This commit build each images with the following arguments:
* IMAGE: Name of the image (e.g dockcross/base, dockcross/manylinux-x64, ...)
* VCS_REF: dockcross/dockcross commit from which this image is built
* VCS_URL: this repository obtained reading remote.origin.url
* BUILD_DATE: Date and time when the build was initiated
Then, within the Dockerfile, the metadata are associated with the image
using the "LABEL" instruction.
See https://docs.docker.com/engine/reference/builder/#/label
The corresponding labels can be found here:
http://label-schema.org/rc1/#build-time-labels
See #28
CMakeForceCompiler was marked deprecated in CMake 3.6.0. It emits many
warnings when using Emscripten. These changes can be removed in a future
version of Emscripten when it is disabled or removed per:
https://github.com/kripken/emscripten/pull/4477
