[Bug-readline] Difficulty compiling readline-6.2 under macosx 10.6.8

[Craig DeForest]

Macosx 10.6.8 has some inconsistencies in implementation that make it difficult 
to compile readline-6.2.  I'm running gcc 4.6.1 with target 
x86_64-apple-darwin10.8.0 (not sure why it's compiling to 10.8 when I have 
system 10.6.8, but most things work OK).  

Compiling readline-6.2 on this system fails in the shlib subdirectory -- there 
is a gcc line "-arch_only `/usr/bin/arch`".  This fails with the error "file 
i386 not found".  The failure appears linked to the (Apple-supplied) 
/usr/bin/arch, which always returns "i386" rather than "x86_64".  Deleting the 
arch_only line solved the problem and I now have a working readline.  

There are other consistency problems on this system, which you can't (of 
course) fix but can work around.  uname -m yields "x86_64" (correct), but uname 
-p yields "i386".  Configure appears to be checking "uname -m" and correctly 
finding "x86_64"; if it finds that and also is on Darwin, perhaps it should 
work around Apple's configuration problem by either not setting the -arch_only 
flag or else by grabbing uname -m rather than /usr/bin/arch or uname -p.

Thanks again for the awesome stuff.  I just realized I've been using emacs and 
gcc for over 20 years!