[MCL-44] new launcher fails to launch on certain linux setups

The new launcher fails to run with a very undescriptive exception:

Starting launcher.
FATAL ERROR: net.minecraft.bootstrap.FatalBootstrapError: Unable to start: java.lang.reflect.InvocationTargetException
	at net.minecraft.bootstrap.Bootstrap.startLauncher(Bootstrap.java:227)
	at net.minecraft.bootstrap.Bootstrap.execute(Bootstrap.java:111)
	at net.minecraft.bootstrap.Bootstrap.main(Bootstrap.java:361)

Please fix the error and restart.

After recompiling the new bootstrap launcher to actually print the InvocationTargetException fully, I get this:

Starting launcher.
java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
	at net.minecraft.bootstrap.Bootstrap.startLauncher(Bootstrap.java:236)
	at net.minecraft.bootstrap.Bootstrap.execute(Bootstrap.java:122)
	at net.minecraft.bootstrap.Bootstrap.main(Bootstrap.java:362)
Caused by: java.lang.InternalError: Unable to load native GTK libraries
	at com.sun.java.swing.plaf.gtk.GTKLookAndFeel.initialize(GTKLookAndFeel.java:1448)
	at javax.swing.UIManager.setLookAndFeel(UIManager.java:535)
	at javax.swing.UIManager.setLookAndFeel(UIManager.java:580)
	at net.minecraft.launcher.Launcher.<init>(Launcher.java:39)
	... 7 more
FATAL ERROR: net.minecraft.bootstrap.FatalBootstrapError: Unable to start: java.lang.reflect.InvocationTargetException
	at net.minecraft.bootstrap.Bootstrap.startLauncher(Bootstrap.java:239)
	at net.minecraft.bootstrap.Bootstrap.execute(Bootstrap.java:122)
	at net.minecraft.bootstrap.Bootstrap.main(Bootstrap.java:362)

Please fix the error and restart.

Perhaps you should try to gracefully fallback to metal or something when the setL&F fails?