Building atlas with clang 3.3 needs excessive memory

[bgschaid@…]

Tried to do a routine upgrade of the installed software. Amongst others:

port outdated
The following installed ports are outdated:
atlas                          3.10.1_2 < 3.10.1_3 

The installed atlas is

port installed atlas
The following ports are currently installed:
  atlas @3.10.1_2+gcc45 (active)

The update started by fetching clang3.3 which made me suspicious because in the past I already had the experience that clang needs much more memory than gcc, but I figured "Hey. Surely the guy who packaged it knows what he's doing". Compilation of atlas took several hours. When I left the computer and returned an hour later it turned out that the disk which previously had 20Gig free had filled because of bloated swap-files. Computer was thus unusable. Only thing I could see from a htop I had running was some program of user macports with 14Gig Virtual and 4.5Gig residual memory

As gcc45 is no longer an option for atlas I did a "port upgrade atlas +gcc46" and the compilation finished after a quarter of an hour. Maybe that has to do with {{ {Warning: GCC compilers on MacOS do not support AVX: downgrading. }}}

Anyway: would be nice if the default settings for the port would be such that it compiles without problems on machines with moderate memory installation (mine has 8Gig. The maximum that fits into that model). Those who need the extra speed that CLang might provide can always choose that variant I think