Note that this also includes a change to the Linux build script to account for a recent
upgrade of the toolchain version used for that platform.
A subsequent change will remove the old source and build products for version 3.1.1.
#jira UE-151140
#rb ruslan.idrisov, brandon.schaefer
#preflight 627aae4e0a5817c9d90b780b
[CL 20228463 by matt johnson in ue5-main branch]
This removes the hard-coded (and incorrect) paths to the libc++ and libc++abi
static libraries in favor of just using the already provided library path and the library
names with the '-l' option.
#rb none
#preflight skip
[CL 19545833 by matt johnson in ue5-main branch]
