feature/skia merged to master - compile failure for Ubuntu 16.04

[Justin Luth]

On Ubuntu 16.04 I needed to add --disable-skia (which let the build 
proceed) because I was getting the following error:

/usr/bin/ld.gold: error: cannot find -lGLX
collect2: error: ld returned 1 exit status
git/libreoffice/external/skia/Library_skia.mk:10: recipe for target 
'git/libreoffice/instdir/program/libskialo.so' failed
make[1]: *** [git/libreoffice/instdir/program/libskialo.so] Error 1

ld.gold --version
GNU gold (GNU Binutils for Ubuntu 2.28) 1.14


I didn't find any reference to this error in a google search, or in the 
skia build notes, so I'm not sure what is missing in order to get this 
to compile on 16.04. Any ideas? I'm assuming that libglx0 (available on 
18.04) is what lets it work there, but there does not seem to be a 
libglx0 for 16.04.

Thanks,

Justin