Use proper array form in swiftc.

mesonbuild/compilers/detect.py

diff --git a/mesonbuild/compilers/detect.py b/mesonbuild/compilers/detect.py
index 72a3533..0a95f90 100644
--- a/mesonbuild/compilers/detect.py
+++ b/mesonbuild/compilers/detect.py
@@ -1248,7 +1248,7 @@
             cls = SwiftCompiler
             linker = guess_nix_linker(env,
                                       exelist, cls, version, for_machine,
-                                      extra_args=[f.name, '-o /dev/null'])
+                                      extra_args=[f.name, '-o', '/dev/null'])
         return cls(
             exelist, version, for_machine, is_cross, info, linker=linker)