gron will fail to link at runtime once OpenBSD removes syscall(2)

[jrick]

I currently see this running gron's master branch on a patched OpenBSD without syscall(2):

$ ./gron
gron:./gron: undefined symbol 'syscall'
ld.so: gron: lazy binding failed!
Killed 

The necessary fixes to use the proper libc stubs instead of the syscall(2) interface have already made their way to gron's dependencies, but gron is not requiring new enough versions yet. Bumping the color module to its latest version (1.15.0) resolves the issue.