Log Message:
Pullup ticket #5851 - requested by gdt
lang/ocaml: build fix

Revisions pulled up:
- lang/ocaml/Makefile                                           1.121
- lang/ocaml/PLIST                                              1.49

-------------------------------------------------------------------
   Module Name:	pkgsrc
   Committed By:	gdt
   Date:		Tue Oct 16 00:19:40 UTC 2018

   Modified Files:
   	pkgsrc/lang/ocaml: Makefile PLIST

   Log Message:
   ocaml: Adjust PLIST for old MacOS

   MacOS before 10.13 lacks the POSIX-required clock_gettime(), and fails
   to build some "instrumented runtime" files.  Conditionalize the PLIST
   and avoid expecting these on older MacOS.

   Based almost entirely on a patch from Ryo Kogule on tech-pkg@, with
   minor munging by me.

   To generate a diff of this commit:
   cvs rdiff -u -r1.120 -r1.121 pkgsrc/lang/ocaml/Makefile
   cvs rdiff -u -r1.48 -r1.49 pkgsrc/lang/ocaml/PLIST