[MacPorts] #60760: netgen @6.2.2004: fatal error: 'optional' file not found

[MacPorts]

#60760: netgen @6.2.2004: fatal error: 'optional' file not found
-------------------------+---------------------------------
  Reporter:  ryandesign  |      Owner:  MarcusCalhoun-Lopez
      Type:  defect      |     Status:  assigned
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:
Resolution:              |   Keywords:
      Port:  netgen      |
-------------------------+---------------------------------
Description changed by ryandesign:

Old description:

> https://build.macports.org/builders/ports-10.12_x86_64-builder/builds/120640/steps
> /install-port/logs/stdio
>
> {{{
> /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_math_netgen/netgen/work/netgen-6.2.2004/libsrc/include/mystdlib.h:22:10:
> fatal error: 'optional' file not found
> #include <optional>
>          ^~~~~~~~~~
> }}}
>
> Optional is a C++ 17 feature so this port should use
> `compiler.cxx_standard 2017`.
>
> I don't see any `-std=c++17` flags in the build so the port shoudl also
> use `configure.cxxflags-append `-std=c++17`.
>
> Note that ports that use "optional" will fail to build on 10.13 until
> https://github.com/macports/macports-base/pull/179  is merged, a new
> version of base is released, and the clang-9.0 port receives a revbump
> (see https://github.com/macports/macports-ports/pull/6971).
>
> Note that ports that use "optional" will never build in 10.7 thru 10.12
> inclusive because their libc++ doesn't support it.

New description:

 https://build.macports.org/builders/ports-10.12_x86_64-builder/builds/120640/steps
 /install-port/logs/stdio

 {{{
 /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_math_netgen/netgen/work/netgen-6.2.2004/libsrc/include/mystdlib.h:22:10:
 fatal error: 'optional' file not found
 #include <optional>
          ^~~~~~~~~~
 }}}

 Optional is a C++ 17 feature so this port should use
 `compiler.cxx_standard 2017`.

 I don't see any `-std=c++17` flags in the build so the port shoudl also
 use `configure.cxxflags-append -std=c++17`.

 Note that ports that use "optional" will fail to build on 10.13 until
 https://github.com/macports/macports-base/pull/179  is merged, a new
 version of base is released, and the clang-9.0 port receives a revbump
 (see https://github.com/macports/macports-ports/pull/6971).

 Note that ports that use "optional" will never build in 10.7 thru 10.12
 inclusive because their libc++ doesn't support it.

--

-- 
Ticket URL: <https://trac.macports.org/ticket/60760#comment:3>
MacPorts <https://www.macports.org/>
Ports system for macOS