lang/ocaml: fix build on armv7

armv7 requires -Wl,-znotext in LDFLAGS (same as i386), added definition for triple target and include term.h in the test for tgetent.

PR: 239157
Approved by: michipili@gmail.com (maintainer timeout), tcberner (mentor)
Differential Revision: https://reviews.freebsd.org/D21085