default configure.cppflags

[Ryan Schmidt]

On Oct 2, 2013, at 19:02, Ryan Schmidt wrote:

> https://trac.macports.org/ticket/40655
> 
> Do we want this in base? There are probably other situations where it's useful too.

One place this would come in handy is for CPPFLAGS in situations when MacPorts' default "`-I${prefix}/include`" is problematic for some build systems. Ideally the build systems should be fixed of course, but when that's difficult, some ports (like abiword) may write "`configure.cppflags -I. -I${prefix}/include`"; with this patch to base, it could be more simply written "`configure.cppflags-prepend -I.`".

But another way to handle that issue is to replace "`-I${prefix}/include`" with "`-isystem${prefix}/include`", and several ports (like freetype, ghostscript and pianobar) do that. Which brings up the question of whether we should change MacPorts' default configure.cppflags to that. Would there be any harm?