Appease clang -Wempty-translation-unit

ebcdic.c:284:7: warning: ISO C requires a translation unit to contain at least one
      declaration [-Wempty-translation-unit]
      ^
1 warning generated.
Reviewed-by: NRich Salz <rsalz@openssl.org>

crypto/ebcdic.c

@@ -3,7 +3,7 @@
 #ifndef CHARSET_EBCDIC
 
 # include <openssl/e_os2.h>
-# if defined(PEDANTIC) || defined(__DECC) || defined(OPENSSL_SYS_MACOSX)
+# if defined(PEDANTIC) || defined(__DECC) || defined(OPENSSL_SYS_MACOSX) || defined(__clang__)
 static void *dummy = &dummy;
 # endif