Fix c++ compilation

Fixes https://github.com/openssl/openssl/issues/532Signed-off-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NTim Hudson <tjh@openssl.org>

include/openssl/e_os2.h

@@ -348,6 +348,8 @@ typedef unsigned __int64 uint64_t;
 #  else
 #   define ossl_inline
 #  endif
+# else
+#  define ossl_inline inline
 # endif
 
 #ifdef  __cplusplus