compilers: Convert args to cc.{links,run} from unix to native

This allows build files to pass -L and -l flags and have them converted
automatically as needed.

mesonbuild/compilers.py

@@ -520,7 +520,8 @@ int main () {{ {1}; }}'''
         ofile = open(srcname, 'w')
         ofile.write(code)
         ofile.close()
-        extra_args = extra_args + self.get_output_args(dstname)
+        extra_args = self.unix_link_flags_to_native(extra_args) + \
+            self.get_output_args(dstname)
         p = self.compile(code, srcname, extra_args)
         try:
             os.remove(dstname)
@@ -539,7 +540,7 @@ int main () {{ {1}; }}'''
         ofile.close()
         exename = srcname + '.exe' # Is guaranteed to be executable on every platform.
         commands = self.get_exelist()
-        commands += extra_args
+        commands += self.unix_link_flags_to_native(extra_args)
         commands.append(srcname)
         commands += self.get_output_args(exename)
         p = subprocess.Popen(commands, cwd=os.path.split(srcname)[0], stdout=subprocess.PIPE, stderr=subprocess.PIPE)