[MacPorts] #67307: glib2 compilation issues with clang

[MacPorts]

#67307: glib2 compilation issues with clang
-----------------------+----------------------
  Reporter:  rmottola  |      Owner:  mascguy
      Type:  defect    |     Status:  assigned
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:
Resolution:            |   Keywords:  leopard
      Port:  glib2     |
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Comment (by kencu):

 Replying to [comment:11 rmottola]:
 >
 > I added
 >
 >
 > {{{
 > configure.cxxflags-append -std=c++11
 > }}}
 >
 > but it still doesn't work.

 With gcc5+ as the compiler, it should work. gcc5+ defaults to c++11 as the
 standard, and automatically uses it's newer libstdc++.dylib and newer
 headers.

 With clang as the compiler, you will have to force non-defaults. You would
 have to add the {{{-std=c++11}}} to the cxxflags as you did, but then you
 also need to force clang to use a newer standard library.

 The usual one on macOS is libc++, so you would make this happen on the
 cxxflags and ldflags {{{-stdlib=libc++}}} for most MacPorts builds. This
 is what we default to and test on 10.6+.

 For our "bastardized" builds on 10.4 and 10.5, we have the hack that lets
 clang use libgcc's headers and libraries. So you have to make this happen
 with the cxxflags (and ldflags) {{{-stdlib=macports-libstdc++}}}. Usually
 that is done by base, by setting this in the Portfile:

 {{{
 compiler.cxx_standard 2011
 }}}

 but then you will have to inspect the build lines to make sure that you
 are not setting the stdlib twice (that may not work out if they are
 different) and that the stdlib setting is also showing up in the ldflags
 (otherwise the link will fail).

-- 
Ticket URL: <https://trac.macports.org/ticket/67307#comment:15>
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