Fix pointer size issue with setbuf() on VMS

setbuf() is only for 32-bit pointers.  If compiled with /POINTER_SIZE=64,
we get a nasty warning about possible loss of data.  However, since
the only pointer used in the call is a FILE *, and the C RTL shouldn't
give us a pointer above the first 4GB, it's safe to turn off the
warning for this call.
Reviewed-by: NAndy Polyakov <appro@openssl.org>

apps/apps.c

@@ -2499,7 +2499,21 @@ BIO *dup_bio_err(int format)
 
 void unbuffer(FILE *fp)
 {
+/*
+ * On VMS, setbuf() will only take 32-bit pointers, and a compilation
+ * with /POINTER_SIZE=64 will give off a MAYLOSEDATA2 warning here.
+ * However, we trust that the C RTL will never give us a FILE pointer
+ * above the first 4 GB of memory, so we simply turn off the warning
+ * temporarily.
+ */
+#if defined(OPENSSL_SYS_VMS) && defined(__DECC)
+# pragma environment save
+# pragma message disable maylosedata2
+#endif
     setbuf(fp, NULL);
+#if defined(OPENSSL_SYS_VMS) && defined(__DECC)
+# pragma environment restore
+#endif
 }
 
 static const char *modestr(char mode, int format)