error: cannot find protocol declaration for 'NSTouchBarDelegate'
gmsh fails to build on OS X 10.9 and earlier. At configuration time it says:
-- Found TouchBar
And when building it says:
.../gmsh-4.5.4-source/Fltk/touchBar.mm:36:41: error: cannot find protocol declaration for 'NSTouchBarDelegate'; did you mean 'NSToolbarDelegate'? @interface TouchBarDelegate : NSObject <NSTouchBarDelegate> ^~~~~~~~~~~~~~~~~~ NSToolbarDelegate
The first TouchBar Macs shipped with macOS 10.12.1.
What's curious is that it builds fine on OS X 10.10 and later. On 10.10 and 10.11 the configuration correctly does not mention finding the TouchBar, and on 10.12 and later the configuration correctly mentions finding it. This suggests that there is something faulty about the method of TouchBar detection. It shouldn't be found on 10.9 or earlier but is.