[U-Boot] [PATCH] Makefile: prevent libgcc to be linked twice

[Mike Frysinger <vapier@gentoo.org>]

On Tuesday 18 October 2011 04:30:27 Nicolas Ferre wrote:
> On 10/17/2011 07:25 PM, Mike Frysinger :
> > On Monday 17 October 2011 09:41:15 Nicolas Ferre wrote:
> >> If we define USE_PRIVATE_LIBGCC, PLATFORM_LIBS is used during
> >> link. During this last link editing, libgcc may be listed twice
> >> and fail.
> >> Prevent this using "filter-out" in top Makefile.
> > 
> > could you please provide more details ?  libgcc should not be listed
> > twice.
> 
> I compile current u-boot with the flowing command line:
> make -j5 CROSS_COMPILE=arm-linux-gnueabi- USE_PRIVATE_LIBGCC=yes
> at91sam9m10g45ek_nandflash

the issue shows up when using the board shortcut, and only when your tree is 
already configured.  if you use at91sam9m10g45ek_nandflash_config and then 
another make, it works fine.  if you start from a clean tree (git clean -x -d), 
it works fine.

this is due to PLATFORM_LIBS appending PLATFORM_LIBGCC when the tree has been 
configured, then exporting PLATFORM_LIBS, then the board shortcut running 
$(MAKE).  the exported PLATFORM_LIBS gets LIBGCC appended a second time.

this issue will show up with any value that gets appended to PLATFORM_LIBS and 
not just libgcc.  the arm code already hits this and deals with it locally.  
seems like we should instead unify this logic, or redo PLATFORM_LIBS so that 
it isn't an issue in the first place.
-mike