Re: [gentoo-amd64] Re: Please suggest settings and flags in /etc/make.conf?

[Frank Peters <frank.peters@comcast.net>]

On Fri, 22 Jan 2010 12:49:27 +0000 (UTC)
Duncan <1i5t5.duncan@cox.net> wrote:

> 
> Meanwhile, it's also worth considering LDFLAGS.  Here's mine:
> 
> LDFLAGS="-Wl,-z,now,--as-needed,-O1,--hash-style=gnu,--sort-common"
> 
> --as-needed is the one most folks will be interested in.  There's talk of 
> eventually making this the Gentoo default, as it can DRAMATICALLY reduce 
> the number of reverse dependency breakage of the sort revdep-rebuild 
> fixes.  I'm talking an order of magnitude reduction, having to rebuild 
> maybe 1/10 of the packages that would have to be rebuilt without it.  
> Problems with this one should now be quite rare indeed,
>

I've been using the "--as-needed" option for some time now and
probably most of my system has been rebuilt with it.

In my experience, the only package where "--as-needed" causes
problems is libdrm, which will not compile using this option.
The solution is to define a specific LDFLAGS variable without
"--as-needed" just for libdrm in the /etc/portage/env directory.

I forget what this method is called, but using the /etc/portage/env
directory is one way to allow CFLAGS, LDFLAGS, etc. to be
customized for individual packages.

Another example of this kind of customization is that both Python
and Sqlite supposedly perform better with "-O3" in the CFLAGS variable.
By making an appropriate entry into /etc/portage/env one can specify
"-O3" just for these packages but use "-O2" for all other packages.

Frank Peters