[Buildroot] [PATCH] infra: do not append an empty LD_LIBRARY_PATH

[Baruch Siach]

Hi Yann,

On Fri, Nov 21, 2014 at 11:53:36PM +0100, Yann E. MORIN wrote:
> When we set LD_LIBRARY_PATH when building our host tools, we append any
> pre-existing value to our custom path:
>         LD_LIBRARY_PATH="$(HOST_DIR)/usr/lib:$(LD_LIBRARY_PATH)"
> 
> But then if LD_LIBRARY_PATH was previously empty, we end up with an
> LD_LIBRARY_PATH that ends with a colon.
> 
> Also, when we check that an existing LD_LIBRARY_PATH does not contain
> CWD, we previously did not look for a zero-length prefix.
> 
> Since 'man ld.so' says of LD_LIBRARY_PATH:
>     A colon-separated list of directories in which to search for ELF
>     libraries at execution-time. Similar to the PATH environment
>     variable.
> 
> And POSIX states about PATH:
>     A zero-length prefix is a legacy feature that indicates the current
>     working directory.
> 
> And bash also recognises a zero-length prefix to searh in CWD:
>     A zero-length (null) directory name in the value of PATH indicates
>     the current directory.
> 
> We may thus end up on a system where a zero-length prefix in
> LD_LIBRARY_PATH is interpreted as VWD.

s/VWD/CWD/

baruch

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