build: detect execinfo library on Linux

build: detect execinfo library on Linux

The library execinfo and its header file can be installed on Alpine Linux
where the backtrace feature is not part of musl libc:
	apk add libexecinfo-dev

As a consequence, this library should not be restricted to BSD only.

At the same time, the library and header are detected once and added
globally to be linked with any application, internal or external.

Fixes: 9065b1fac65f ("build: fix dependency on execinfo for BSD meson builds")
Cc: stable@dpdk.org
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: David Marchand <david.marchand@redhat.com>