default configure.cppflags

[Daniel J. Luke]

On Oct 2, 2013, at 8:14 PM, Ryan Schmidt <ryandesign at macports.org> wrote:
> 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.`".

+1 to this being possibly useful

> 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?


where is -isystem documented? If it does what it looks like it does, it could possibly cause issues depending on what is in ${prefix}/include (ie, if there's some header that would override a system header).

Actually, even -I${prefix}/include is too big of a stick since builds pick up installed ports even if they shouldn't (which is why, way back in the mists of time, we didn't set that by default). Hopefully some version of sandboxing/trace mode will eventually fix this (so that only files belonging to ports that are listed as dependencies appear as if they exist to software that's being built).

--
Daniel J. Luke                                                                   
+========================================================+                        
| *---------------- dluke at geeklair.net ----------------* |                          
| *-------------- http://www.geeklair.net -------------* |                          
+========================================================+                        
|   Opinions expressed are mine and do not necessarily   |                          
|          reflect the opinions of my employer.          |                          
+========================================================+