debug/ltrace: fix LDFLAGS for libsupc++ and libiberty

The configure script correctly detects libsupc++ and libiberty, but in
the linker stage it tries to link in both libraries without taking care
of the test result.

Signed-off-by: Robert Schwebel <r.schwebel@pengutronix.de>
[yann.morin.1998@anciens.enib.fr: rework patch depth to be -p1]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

source "config/backend.in"

source "config/global.in"

source "config/target.in"

source "config/toolchain.in"

source "config/kernel.in"

source "config/binutils.in"

source "config/cc.in"

source "config/libc.in"

source "config/debug.in"

source "config/companion_libs.in"

source "config/companion_tools.in"

source "config/test_suite.in"