Auto merge of #2442 - tklauser:libc-test-duplicate-headers, r=JohnTitor

libc-test: remove duplicate headers from test_apple

Author: bors

libc-test/build.rs

@@ -212,11 +212,9 @@ fn test_apple(target: &str) {
         "net/if_dl.h",
         "net/if_utun.h",
         "net/route.h",
-        "net/route.h",
         "netdb.h",
         "netinet/if_ether.h",
         "netinet/in.h",
-        "netinet/in.h",
         "netinet/ip.h",
         "netinet/tcp.h",
         "netinet/udp.h",