[MacPorts] #53415: glpk 4.61 does not build on Mac OS X 10.6.8, Snow Leopard, because "Reentrancy needs complier support for TLS"

[MacPorts]

#53415: glpk 4.61 does not build on Mac OS X 10.6.8, Snow Leopard, because
"Reentrancy needs complier support for TLS"
------------------------+-----------------
  Reporter:  ballapete  |      Owner:
      Type:  defect     |     Status:  new
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:
Resolution:             |   Keywords:
      Port:  glpk       |
------------------------+-----------------

Comment (by kencu):

 Snow Leopard has no thread-local storage with libc++ or with the standard
 stdlibc++ that you get to with llvm-gcc-4.2. So on those build systems,
 you would need to use `--disable-reentrant`.

 However, Snow Leopard does support thread-local storage with the newer
 libgcc that you can access with gcc5+ (or with Marcus' recent clang-3.9
 macports-libstdc++ shenanigans)
 {{{

 checking whether to enable reentrancy support... yes
 checking for thread local storage (TLS) class specifier... _Thread_local
 checking if libtool needs -no-undefined flag to build shared libraries...
 no
 }}}
 and in that configuration, glpk will build without modification. So it's
 not trivial to make a hard and fast rule about this.

 Brainless approach -- just `--disable-reentrant` on 10.6 and be done with
 it.

 Artistic approach - check for the build system and disable it selectively,
 if cxx_stdlib ne macports-libstdc++. May be more trouble than it's worth?

--
Ticket URL: <https://trac.macports.org/ticket/53415#comment:2>
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