[MacPorts] #57007: root6 port results in ambiguous include directories after 6.14

[MacPorts]

#57007: root6 port results in ambiguous include directories after 6.14
---------------------+--------------------
 Reporter:  olupton  |      Owner:  (none)
     Type:  defect   |     Status:  new
 Priority:  Normal   |  Milestone:
Component:  ports    |    Version:  2.5.3
 Keywords:           |       Port:  root6
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 With the most recent verison(s) of the root6 port I have had problems
 compiling local code linking against ROOT.

 The problem seems to be that in the default MacPorts installation of root6
 the ROOT headers are accessible both at:
 /opt/local/libexec/root6/include/root (returned by `root-config --incdir`)
 and:
 /opt/local/include/root{,6}

 And since 6.14 at least one header with the same name exists at multiple
 levels of the header file structure:
 MD5 (/opt/local/libexec/root6/include/root/RConfig.h) =
 c2c2d44a3228fcbf9943048bfca2cb27
 MD5 (/opt/local/libexec/root6/include/root/ROOT/RConfig.h) =
 5d2a7a998a363947acd947487a666bea

 (see e.g. https://root.cern.ch/doc/v614/ROOT_2RConfig_8h.html and the non-
 existence of the same page for 6.12)

 When (automatically-generated) code tries to include the latter, i.e.
 #include <ROOT/RConfig.h>, then, if /opt/local/include is in the include
 path, /opt/local/include/root/RConfig.h is found instead (with a warning
 about non-portable filenames because the case doesn't match,
 -Wnonportable-include-path), and compilation fails because the wrong one
 of the two RConfig.h is picked up (errors like "error: use of undeclared
 identifier 'R__likely'" -- included so hopefully Google finds this
 ticket).

 A minimal workaround is to remove the /opt/local/include/root{,6} symlinks
 and make sure /opt/local/libexec/root6/include/root is in the include path
 for compilation. This seems a bit ugly, but so do all the other
 solutions...

 Possibilities I see:
 - Remove /opt/local/include/root{,6} symlinks: seems wrong to not have the
 headers somewhere under /opt/local/include
 - Move the headers one directory up the tree under /opt/local/include,
 i.e.  ln -s /opt/local/libexec/root6/include/root/RConfig.h
 /opt/local/include/RConfig.h repeated for every ROOT header: involves a
 large number of links, but does integrate ROOT into the /opt/local tree a
 bit better.
 - Consider it a bug on my part that /opt/local/include is in the include
 path when compiling against ROOT: seems unreasonable, many other packages'
 headers are only available here.
 - Consider it a bug on my part that /opt/local/include comes before
 /opt/local/libexec/root6/include in the include path: doesn't seem very
 robust/reasonable to expect all external dependencies to respect this
 convention

-- 
Ticket URL: <https://trac.macports.org/ticket/57007>
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