[MacPorts] #59973: cmake-1.1 portgroup debug variant adds -fno-limit-debug-info before port has a chance to specify compiler (was: broken mpicc-openmpi-gcc9 causes flann +gcc9 +debug +openmpi +python37 build failure)

[MacPorts]

#59973: cmake-1.1 portgroup debug variant adds -fno-limit-debug-info before port
has a chance to specify compiler
------------------------------+------------------------
  Reporter:  TheLastLovemark  |      Owner:  ryandesign
      Type:  defect           |     Status:  accepted
  Priority:  Normal           |  Milestone:
 Component:  ports            |    Version:  2.6.2
Resolution:                   |   Keywords:  haspatch
      Port:                   |
------------------------------+------------------------
Changes (by ryandesign):

 * owner:  (none) => ryandesign
 * keywords:   => haspatch
 * status:  new => accepted
 * port:  flann =>


Comment:

 It has nothing to do with openmpi, nor even with flann. The problem
 appears to be that the flag `-fno-limit-debug-info` is being supplied to
 gcc-mp-9, and that is not a flag that gcc understands; it is a clang-
 specific flag, as far as I have been able to determine.

 The `-fno-limit-debug-info` flag is coming from the cmake-1.1 portgroup,
 which intends to add that flag when the +debug variant is set (which it is
 in your case) and the compiler is clang (which is not supposed to be the
 case here). But clang is the default compiler. It seems that the cmake-1.1
 portgroup is checking what the compiler is before the port has had a
 chance to specify what compiler it wants, so the cmake-1.1 portgroup is
 seeing the default compiler rather than the one the port ultimately chose.

 If you weren't using both the +debug variant and a gcc variant, you
 wouldn't see this problem, so if you can do without one or the other that
 would be a workaround.

 Putting everything that the debug variant does within a `pre-configure {
 ... }` block seems to work for me to fix this specific problem, though I
 don't know if it'll cause other problems. I've submitted
 https://github.com/macports/macports-ports/pull/6171 to fix this.

 FYI, anything you do with `sudo port select` is for your own benefit on
 the command line. Other ports you install should not be influenced by what
 you have selected. (If they are, it is a bug in that port.)

-- 
Ticket URL: <https://trac.macports.org/ticket/59973#comment:2>
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