Remove cross_prefix from ln command.

patch by Matthias Schneider, ma30002000 yahoo de


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@10515 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

configure

@@ -1220,7 +1220,6 @@ cc="${cross_prefix}${cc}"
 ar="${cross_prefix}${ar}"
 ranlib="${cross_prefix}${ranlib}"
 strip="${cross_prefix}${strip}"
-ln_s="${cross_prefix}${ln_s}"
 
 # we need to build at least one lib type
 if ! enabled_any static shared; then