MacPorts wants to install apple-gcc42 on 10.6 all of a sudden?

[Ned Deily]

In article <FF6B7AC5-A89F-4AE1-9AA9-7BF5B173B780 at macports.org>,
 Lawrence Velázquez <larryv at macports.org> wrote:
> On Apr 22, 2013, at 10:16 AM, René J.V. Bertin <rjvbertin at gmail.com> wrote: 
> > On Apr 22, 2013, at 15:12, Clemens Lang wrote:
> >> While it is uncommon to have multiple Xcode versions I guess if you have
> >> a patch to fix this we'd be happy to apply it.
> > As I said, I executed xcode-select /Developer to make Xcode 3.2 the default 
> > again. Not sure what I should patch nor how for an automated fix. 
> Note that (as far as I know) xcode-select does not swap out the tools 
> installed to /usr/bin (the Command Line / UNIX Development tools), which are 
> the tools that MacPorts generally uses for building.

That's correct.  xcode-select sets the defaults that are used by several 
other build tools, primarily xcodebuild and xcrun but it has no effect 
on what is installed in system locations.  If you allowed the Xcode 4.2 
Installer to install the command tools package (I'm not sure what the 
package name is for Xcode 4.2), you would need to re-install the 3.2.6 
UNIX Development package using the Xcode 3.2.6 Installer to get the 
proper executables and header files installed in /usr/bin, /usr/include, 
/System/Frameworks, et al.  First, though, you should uninstall the 4.2 
command tools by using the uninstaller script from the Xcode 4.2 
/Developer directory:

sudo <Xcode4.2>/Library/uninstall-devtools --mode=unixdev
sudo <Xcode4.2>/Library/uninstall-devtools --mode=systemsupport

That will leave the files in the Xcode 4.2 directory unchanged so it is 
still possible to use the compilers and SDKs there using xcrun and 
xcodebuild.  To remove all of Xcode 4.2:

sudo <Xcode4.2>/Library/uninstall-devtools --mode=all

Then run the 3.2.6 installer and customize to ensure that the "UNIX 
Development" package is selected.

FTR, current versions of Xcode 4.x on 10.7 and 10.8 have moved the 
management of the command line tools ("UNIX Development") to within the 
expanded Xcode.app and do not use /Developer dirs.

-- 
 Ned Deily,
 nad at acm.org