[MacPorts] #55577: getting rid of unforeseen -I${prefix}/include option adding and its potential side-effects

[MacPorts]

#55577: getting rid of unforeseen -I${prefix}/include option adding and its
potential side-effects
--------------------------+-----------------
  Reporter:  RJVB         |      Owner:
      Type:  enhancement  |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:
Resolution:               |   Keywords:
      Port:  pcre, glib2  |
--------------------------+-----------------

Comment (by ryandesign):

 Replying to [comment:8 RJVB]:
 > I cannot really comment on the idea of using -isystem . It might work as
 you suggest, but it might depend on whether clang or gcc is used.

 All the compilers we use support `-isystem`. gcc-4.0 didn't support it
 properly, but we don't use that anymore.

 Replying to [comment:9 RJVB]:
 > In fact, how does the resolution of build dependencies work?
 > - If the (pkgconfig) install is triggered from within the evaluation of
 the dependent port (say before the pre-configure step) the CFLAGS
 definition will indeed not be altered after the install
 > - If the install is somehow done before the dependent port is parsed (or
 if the Portfile is parsed again after that install) the check above should
 pass

 The build dependencies will be installed by the time the configure phase
 starts. They might not be there in earlier phases, nor at the time the
 portfile is parsed.

--
Ticket URL: <https://trac.macports.org/ticket/55577#comment:10>
MacPorts <https://www.macports.org/>
Ports system for macOS