scripts/xldd: fix typoes

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
(transplanted from dbecd99ecba51980ec9938b1313effeb45ef2ce7)

scripts/xldd: install only when shared libs enabled

When the toolchain has no support for shared libraries, there is no
point in installing the cross-ldd helper.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
(transplanted from 032ae3253a655d859f25a5c2bac1b72051f950b0)

scripts/xldd: try to handle RPATH tags

The RPATH tags allow a binary to tell the dynamic linker what
directories to search for libraries. The so-added paths are
searched into before any other paths.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

scripts/xldd: better handle the origin of the library

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

scripts/xldd: avoid reporting duplicates

Once a NEEDED dependency has been solved, do not report it
if other dependencies depend on it.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

script/xldd: add debug traces

Add debug traces to help understand how xldd finds the
libraries, what directories it scans, in which order...

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

scripts/xldd: parse /etc/ld.so.conf

Scan /etc/ld.so.conf for paths to search for libraries.
Also follow include directives in there.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>