meson: add static linker var

If an AR var is not exported, meson will use static linker from the host

Author: matt-sm

foreign_cc/meson.bzl

@@ -81,6 +81,8 @@ def _create_meson_script(configureParameters):
         script.append("##export_var## CC {}".format(_absolutize(ctx.workspace_name, tools.cc)))
     if " " not in tools.cxx:
         script.append("##export_var## CXX {}".format(_absolutize(ctx.workspace_name, tools.cxx)))
+    if " " not in tools.cxx_linker_static:
+        script.append("##export_var## AR {}".format(_absolutize(ctx.workspace_name, tools.cxx_linker_static)))
 
     copts = flags.cc
     cxxopts = flags.cxx