[MacPorts] #50958: py-graph-tool fails to build with clang OpenMP option (configure.args=--enable-openmp)

[MacPorts]

#50958: py-graph-tool fails to build with clang OpenMP option (configure.args
=--enable-openmp)
----------------------------+--------------------------------------------
  Reporter:  s.t.smith@…    |      Owner:  macports-tickets@…
      Type:  defect         |     Status:  new
  Priority:  Normal         |  Milestone:
 Component:  ports          |    Version:  2.3.4
Resolution:                 |   Keywords:  graph-tool clang openmp libomp
      Port:  py-graph-tool  |
----------------------------+--------------------------------------------

Comment (by s.t.smith@…):

 The feedback from the upstream ticket mentions that omp's parallel if
 clause has a "`parallel`"-named qualifier, which causes the compilation
 problem. https://trac.macports.org/ticket/50983#comment:8

 I confirm that replacing the variable name "`parallel`" with
 "`parallel_enabled`" yields a successful compile. Patch files attached.

 Replying to [comment:7 larryv@…]:
 > [http://llvm.org/releases/3.8.0/tools/clang/docs/ReleaseNotes.html
 #openmp-support-in-clang Clang supports] directive name modifiers in
 OpenMP 4.5 `if` clauses. From §2.12 of the [http://www.openmp.org/mp-
 documents/openmp-4.5.pdf OpenMP 4.5 spec]:
 > {{{
 > #!html
 > <blockquote>
 > <p>The syntax of the <code>if</code> clause is as follows:</p>
 > <div style="border: thin solid; padding: 0.5em;">
 > <code>if(</code><span style="font-style: italic;">[directive-name-
 modifier</span><code> :</code><span style="font-style: italic;">]scalar-
 expression</span><code>)</code>
 > </div>
 > </blockquote>
 > }}}
 >
 > And from §2.5:
 > {{{
 > #!html
 > <blockquote>
 > <p>The syntax of the <code>parallel</code> construct is as follows:</p>
 > <div style="border: thin solid; padding: 0.5em;">
 > <code>#pragma omp parallel</code> <span style="font-style:
 italic;">[clause[[,]clause]...]new-line</span><br/>
 > <span style="font-style: italic; margin-left: 1cm;">structured-
 block</span>
 > </div>
 > <p>where <em>clause</em> is one of the following:</p>
 > <div style="margin-left: 1cm;">
 > <code>if(</code><span style="font-style: italic;">[</span><code>parallel
 :</code><span style="font-style: italic;">]scalar-
 expression</span><code>)</code>
 > </div>
 > …
 > </blockquote>
 > }}}
 >
 > This seems to make “parallel” a sort of reserved word that requires a
 trailing colon, so I doubt LLVM upstream would consider this a bug,
 although you’re free to [https://llvm.org/bugs/ submit a report]. I
 suggest that graph-tool simply use any other variable name.

-- 
Ticket URL: <https://trac.macports.org/ticket/50958#comment:10>
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