FS-7031 [unimrcp] revert configure.gnu change- doesn't work when using non-source build dir.

libs/unimrcp/configure.gnu

 #! /bin/sh
-srcpath=$(pwd)
-$srcpath/configure "$@" --with-apr=$srcpath/../apr --disable-shared --with-pic --with-apr-util=$srcpath/../apr-util --with-sofia-sip=$srcpath/../sofia-sip
-
+srcpath=$(dirname $0 2>/dev/null )  || srcpath="."
+$srcpath/configure "$@" --with-apr=../apr --disable-shared --with-pic --with-apr-util=../apr-util --with-sofia-sip=../sofia-sip