libart_lgpl @2.3.21: Don't create flat-namespace dylib on Yosemite

[ryandesign (Ryan Carsten Schmidt)]

This fixes the well-known libtool-generated configure script dylib creation bug on OS X 10.10 and later, with the usual patch we've used in many other ports already. See #44596 for history.

Before

$ port installed libart_lgpl
The following ports are currently installed:
  libart_lgpl @2.3.21_0+universal (active)
$ otool -hv /opt/local/lib/libart_lgpl_2.2.dylib
Mach header
      magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
MH_MAGIC_64  X86_64        ALL  0x00       DYLIB    13       1536 DYLDLINK NO_REEXPORTED_DYLIBS

After

$ port installed libart_lgpl
The following ports are currently installed:
  libart_lgpl @2.3.21_1+universal (active)
$ otool -hv /opt/local/lib/libart_lgpl_2.2.dylib
Mach header
      magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
MH_MAGIC_64  X86_64        ALL  0x00       DYLIB    13       1536   NOUNDEFS DYLDLINK TWOLEVEL NO_REEXPORTED_DYLIBS

[tobypeterson]

Go for it, feel free to make the port openmaintainer while you're at it. (github PRs are preferable, don't require me to be on my laptop...)

[ryandesign (Ryan Carsten Schmidt)]

In 58552b34/macports-ports:

libart_lgpl: Don't create flat-namespace dylib on Yosemite

Also add openmaintainer.

Closes: #53531