boost187: build fails for 10.10 and earlier: missing TARGET_OS_IOS

[mascguy (Christopher Nielsen)]

Use of legacysupport is probably the way to go, as there are also several missing identifiers for 10.7 and earlier.

[Christopher Nielsen <mascguy@…>]

In 738b5e689ee6cb7d1dc2480d73c2853937ffef39/macports-ports (master):

boost187: use legacysupport for 10.10 and earlier

Fixes: #71682

[mascguy (Christopher Nielsen)]

Ah, it looks like the bootstrap process - which builds engine b2 - may not be respecting ld-related flags. This results in undefined symbols for items provided by legacysupport, including clock_gettime.

Should be fairly simple to patch though.

[barracuda156]

Yeah, it fails now:

> g++ -x c++ -std=c++11 -pthread -O2 -s -DNDEBUG bindjam.cpp builtins.cpp class.cpp command.cpp compile.cpp constants.cpp cwd.cpp debug.cpp debugger.cpp events.cpp execcmd.cpp execnt.cpp execunix.cpp filent.cpp filesys.cpp fileunix.cpp frames.cpp function.cpp glob.cpp hash.cpp hcache.cpp hdrmacro.cpp headers.cpp jam_strings.cpp jam.cpp jamgram.cpp lists.cpp make.cpp make1.cpp md5.cpp mem.cpp modules.cpp native.cpp option.cpp output.cpp parse.cpp pathnt.cpp pathsys.cpp pathunix.cpp regexp.cpp rules.cpp scan.cpp search.cpp startup.cpp tasks.cpp timestamp.cpp value.cpp variable.cpp w32_getreg.cpp mod_command_db.cpp mod_db.cpp mod_jam_builtin.cpp mod_jam_class.cpp mod_jam_errors.cpp mod_jam_modules.cpp mod_order.cpp mod_path.cpp mod_property_set.cpp mod_regex.cpp mod_sequence.cpp mod_set.cpp mod_string.cpp mod_summary.cpp mod_sysinfo.cpp mod_version.cpp -o b2
ld: warning: option -s is obsolete and being ignored
Undefined symbols:
  "_clock_gettime", referenced from:
      __Z17timestamp_currentP9timestamp in ccr6sh1A.o
ld: symbol(s) not found
collect2: error: ld returned 1 exit status

Failed to build B2 build engine

[BjarneDMat]

​https://github.com/macports/macports-ports/pull/28665