How to compile native extension with C++11 features? (DEF-2594) (SOLVED)

Another build error for Android showed up. “Build failed: Failed to copy classes.dex”.
Wasn’t there before.

eclipse.buildId=unknown
java.version=1.8.0_05
java.vendor=Oracle Corporation
BootLoader constants: OS=macosx, ARCH=x86_64, WS=cocoa, NL=en_US
Framework arguments:  -keyring /Users/lerg/.eclipse_keyring -showlocation
Command-line arguments:  -os macosx -ws cocoa -arch x86_64 -keyring /Users/lerg/.eclipse_keyring -showlocation

Error
Fri Apr 07 22:02:06 YEKT 2017
Unable to bundle application

org.eclipse.core.internal.resources.ResourceException: Errors occurred during the build.
	at org.eclipse.core.internal.resources.Project$1.run(Project.java:620)
	at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2344)
	at org.eclipse.core.internal.resources.Project.internalBuild(Project.java:597)
	at org.eclipse.core.internal.resources.Project.build(Project.java:124)
	at com.dynamo.cr.editor.handlers.AbstractBundleHandler$BundleRunnable.buildProject(AbstractBundleHandler.java:63)
	at com.dynamo.cr.editor.handlers.AbstractBundleHandler$BundleRunnable.run(AbstractBundleHandler.java:72)
	at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)
Contains: Errors running builder 'Content Builder' on project 'extension-openal'.
org.eclipse.core.runtime.CoreException: Build failed: Failed to copy classes.dex to /Applications/Defold/branches/59862/30136/main/build/armv7-android/classes.dex
	at com.dynamo.cr.editor.builders.ContentBuilder.buildLocal(ContentBuilder.java:176)
	at com.dynamo.cr.editor.builders.ContentBuilder.build(ContentBuilder.java:80)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:726)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:199)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:321)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:396)
	at org.eclipse.core.internal.resources.Project$1.run(Project.java:618)
	at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2344)
	at org.eclipse.core.internal.resources.Project.internalBuild(Project.java:597)
	at org.eclipse.core.internal.resources.Project.build(Project.java:124)
	at com.dynamo.cr.editor.handlers.AbstractBundleHandler$BundleRunnable.buildProject(AbstractBundleHandler.java:63)
	at com.dynamo.cr.editor.handlers.AbstractBundleHandler$BundleRunnable.run(AbstractBundleHandler.java:72)
	at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)
Caused by: com.dynamo.bob.CompileExceptionError: Failed to copy classes.dex to /Applications/Defold/branches/59862/30136/main/build/armv7-android/classes.dex
	at com.dynamo.bob.bundle.BundleHelper.buildEngineRemote(BundleHelper.java:246)
	at com.dynamo.bob.Project.buildEngine(Project.java:540)
	at com.dynamo.bob.Project.doBuild(Project.java:589)
	at com.dynamo.bob.Project.build(Project.java:329)
	at com.dynamo.cr.editor.builders.ContentBuilder.buildLocal(ContentBuilder.java:134)
	... 13 more
Contains: Build failed: Failed to copy classes.dex to /Applications/Defold/branches/59862/30136/main/build/armv7-android/classes.dex
com.dynamo.bob.CompileExceptionError: Failed to copy classes.dex to /Applications/Defold/branches/59862/30136/main/build/armv7-android/classes.dex
	at com.dynamo.bob.bundle.BundleHelper.buildEngineRemote(BundleHelper.java:246)
	at com.dynamo.bob.Project.buildEngine(Project.java:540)
	at com.dynamo.bob.Project.doBuild(Project.java:589)
	at com.dynamo.bob.Project.build(Project.java:329)
	at com.dynamo.cr.editor.builders.ContentBuilder.buildLocal(ContentBuilder.java:134)
	at com.dynamo.cr.editor.builders.ContentBuilder.build(ContentBuilder.java:80)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:726)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:199)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:321)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:396)
	at org.eclipse.core.internal.resources.Project$1.run(Project.java:618)
	at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2344)
	at org.eclipse.core.internal.resources.Project.internalBuild(Project.java:597)
	at org.eclipse.core.internal.resources.Project.build(Project.java:124)
	at com.dynamo.cr.editor.handlers.AbstractBundleHandler$BundleRunnable.buildProject(AbstractBundleHandler.java:63)
	at com.dynamo.cr.editor.handlers.AbstractBundleHandler$BundleRunnable.run(AbstractBundleHandler.java:72)
	at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)

A work in progress for the Android packaging?