RFR(XXS): 8214007: Fix sun.awt.nativedebug on X11 platforms

[Volker Simonis]

Hi,

can I please have a review for the following trivial fix:

http://cr.openjdk.java.net/~simonis/webrevs/2018/8214007/
https://bugs.openjdk.java.net/browse/JDK-8214007

AWT supports some kind of native logging which can be enabled with
"-Dsun.awt.nativedebug=true -Dawtdebug.ctrace=true".

Unfortunately this doesn't work on X platforms any more because both,
libawt and libawt_xawt end up with a copy of debug_trace.o. Among
others, debug_trace.o contains the static variable
GlobalTracingEnabled which denotes the tracing state. This obviously
can't work if the final executable contains several instances of this
variable.

The fix is trivial. Remove "common/awt/debug" from the set of sources
for libawt_xawt. libawt_xawt is linked against libawt (which already
contains debug_trace.o) anyway, so this is no problem.

Thank you and best regards,
Volker