[MacPorts] #62801: lilypond 2.22.1_0: fails to build (macOS 11.3)

[MacPorts]

#62801: lilypond 2.22.1_0: fails to build (macOS 11.3)
---------------------------+---------------------------
  Reporter:  emcrisostomo  |      Owner:  nerdling
      Type:  defect        |     Status:  assigned
  Priority:  Normal        |  Milestone:
 Component:  ports         |    Version:
Resolution:                |   Keywords:  bigsur x86_64
      Port:  lilypond      |
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Comment (by emcrisostomo):

 That line in {{{FlexLexer.h}}} hasn't been modified at least in the past 6
 years.  I guess this is not 'just a flex issue': C++11 introduced the
 {{{override}}} specifier, and compiler settings ({{{-Werror,-Wsuggest-
 override}}}) are now forcing this warning to be treated as an error.  We
 could:

 * Open an issue upstream to updated flex and make it more C++11 friendly.
 * Temporarily fix {{{FlexLexer.h}}}, but I guess the solution would be
 more complex than just adding the {{{override}}} specifier to the
 {{{yyFlexLexer::yyFlexLexer}}} member function as @ggruener found out: it
 would need to be C++-version aware, otherwise it would fail to compile
 with older compilers.
 * Modify the compiler settings to disable that error (I don't really feel
 comfortable with relaxing compiler settings this way).
 * Temporarily patch the {{{lilypond}}} sources so that a private version
 of the {{{flex}}} headers are copied in the build directory, patched, and
 compiled.

 Any other ideas?

 I've open an issue upstream: https://github.com/westes/flex/issues/486

 If all this is correct, I would define an {{{OVERRIDE}}} macro
 conditionally, depending on C++ version, and I'm willing to patch
 {{{flex}}} sources and send a PR upstream.  Anybody willing to sanity-
 check this reasoning?

-- 
Ticket URL: <https://trac.macports.org/ticket/62801#comment:6>
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