cc-wrapper: Enter C++ mode when -lc++ is passed

When linking C++ programs in LLVM we're currently explicitly passing
in -lc++abi as this appears to be required by recent versions of
Clang. However, it also appears to b common for packages to use
the C compiler to link binaries which uses C++, in which case they
do pass in -lc++. This changes the wrapper to also take this into
consideration and enter "C++ mode" whenever -lc++ is passed as an
argument.

Fixes #166205

pkgs/build-support/cc-wrapper/cc-wrapper.sh

@@ -48,6 +48,7 @@ while (( "$n" < "$nParams" )); do
         -nostdlib) cxxLibrary=0 ;;
         -x*-header) dontLink=1 ;; # both `-x c-header` and `-xc-header` are accepted by clang
         -xc++*) isCxx=1 ;;        # both `-xc++` and `-x c++` are accepted by clang
+        -lc++*) isCxx=1 ;;
         -x)
             case "$p2" in
                 *-header) dontLink=1 ;;