o_fopen.c,rand/randfile.c: compensate for e_os.h omission.

At earlier point e_os.h was omitted from a number of headers (in order
to emphasize OS neutrality), but this affected o_fopen.c and randfile.c
which are not OS-neutral, and contain some Win32-specific code.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5676)

crypto/o_fopen.c

@@ -12,6 +12,9 @@
 #if !defined(OPENSSL_NO_STDIO)
 
 # include <stdio.h>
+# ifdef _WIN32
+#  include <windows.h>
+# endif
 
 FILE *openssl_fopen(const char *filename, const char *mode)
 {

crypto/rand/randfile.c

@@ -26,7 +26,12 @@
 # include <sys/stat.h>
 # include <fcntl.h>
 # ifdef _WIN32
+#  include <windows.h>
 #  include <io.h>
+#  define stat    _stat
+#  define chmod   _chmod
+#  define open    _open
+#  define fdopen  _fdopen
 # endif
 #endif
 
@@ -41,13 +46,6 @@
 #   define S_ISREG(m) ((m) & S_IFREG)
 # endif
 
-#ifdef _WIN32
-# define stat    _stat
-# define chmod   _chmod
-# define open    _open
-# define fdopen  _fdopen
-#endif
-
 #define RAND_FILE_SIZE 1024
 #define RFILE ".rnd"