build: tidy up and simplify setmode() detection and use

- move macro to `curl_setup.h` (from curlx), and rename.
  It's required by src, test servers, libtests. Also used by unit/tunit,
  (which is fixable but this patch doesn't touch it.)
- special-case it for Windows/Cygwin/MS-DOS.
- build: drop `setmode()`/`_setmode()` detection.
  This also avoids detecting the different `setmode()` on BSDs,
  and a lot of complexity and overhead.
- use `CURL_O_BINARY`.

Follow-up to 250d613763 #15787
Follow-up to 5e70566094 #15169

Closes #20539

lib/Makefile.inc

@@ -45,7 +45,6 @@ LIB_CURLX_CFILES =      \
 
 LIB_CURLX_HFILES =      \
   curlx/base64.h        \
-  curlx/binmode.h       \
   curlx/basename.h      \
   curlx/curlx.h         \
   curlx/dynbuf.h        \

lib/config-win32.h

@@ -117,12 +117,6 @@
 /* Define if you have the setlocale function. */
 #define HAVE_SETLOCALE 1
 
-/* Define if you have the setmode function. */
-#define HAVE_SETMODE 1
-
-/* Define if you have the _setmode function. */
-#define HAVE__SETMODE 1
-
 /* Define if you have the socket function. */
 #define HAVE_SOCKET 1
 

lib/curl_config-cmake.h.in

@@ -484,12 +484,6 @@
 /* Define to 1 if you have the `setlocale' function. */
 #cmakedefine HAVE_SETLOCALE 1
 
-/* Define to 1 if you have the `setmode' function. */
-#cmakedefine HAVE_SETMODE 1
-
-/* Define to 1 if you have the `_setmode' function. */
-#cmakedefine HAVE__SETMODE 1
-
 /* Define to 1 if you have the `setrlimit' function. */
 #cmakedefine HAVE_SETRLIMIT 1
 

lib/curl_setup.h

@@ -868,14 +868,23 @@
 
 /* Since O_BINARY is used in bitmasks, setting it to zero makes it usable in
    source code but yet it does not ruin anything */
-#ifdef _O_BINARY  /* for _WIN32 */
+#ifdef _O_BINARY  /* for _WIN32 || MSDOS */
 #define CURL_O_BINARY _O_BINARY
-#elif defined(O_BINARY)
+#elif defined(O_BINARY)  /* __CYGWIN__ */
 #define CURL_O_BINARY O_BINARY
 #else
 #define CURL_O_BINARY 0
 #endif
 
+/* Requires io.h when available */
+#ifdef MSDOS
+#define CURL_BINMODE(stream) (void)setmode(fileno(stream), CURL_O_BINARY)
+#elif defined(_WIN32) || defined(__CYGWIN__)
+#define CURL_BINMODE(stream) (void)_setmode(fileno(stream), CURL_O_BINARY)
+#else
+#define CURL_BINMODE(stream) (void)stream
+#endif
+
 /* In Windows the default file mode is text but an application can override it.
 Therefore we specify it explicitly. https://github.com/curl/curl/pull/258
 */

lib/curlx/binmode.h

@@ -1,39 +0,0 @@
-#ifndef HEADER_CURL_TOOL_BINMODE_H
-#define HEADER_CURL_TOOL_BINMODE_H
-/***************************************************************************
- *                                  _   _ ____  _
- *  Project                     ___| | | |  _ \| |
- *                             / __| | | | |_) | |
- *                            | (__| |_| |  _ <| |___
- *                             \___|\___/|_| \_\_____|
- *
- * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
- *
- * This software is licensed as described in the file COPYING, which
- * you should have received as part of this distribution. The terms
- * are also available at https://curl.se/docs/copyright.html.
- *
- * You may opt to use, copy, modify, merge, publish, distribute and/or sell
- * copies of the Software, and permit persons to whom the Software is
- * furnished to do so, under the terms of the COPYING file.
- *
- * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
- * KIND, either express or implied.
- *
- * SPDX-License-Identifier: curl
- *
- ***************************************************************************/
-#include "../curl_setup.h"
-
-#if (defined(HAVE_SETMODE) || defined(HAVE__SETMODE)) && defined(O_BINARY)
-/* Requires io.h and/or fcntl.h when available */
-#ifdef HAVE__SETMODE
-#  define CURLX_SET_BINMODE(stream)  (void)_setmode(fileno(stream), O_BINARY)
-#else
-#  define CURLX_SET_BINMODE(stream)  (void)setmode(fileno(stream), O_BINARY)
-#endif
-#else
-#  define CURLX_SET_BINMODE(stream)  (void)stream
-#endif
-
-#endif /* HEADER_CURL_TOOL_BINMODE_H */

lib/curlx/curlx.h

@@ -33,7 +33,6 @@
 
 #include "base64.h" /* for curlx_base64* */
 #include "basename.h" /* for curlx_basename() */
-#include "binmode.h" /* for macro CURLX_SET_BINMODE() */
 #include "dynbuf.h" /* for curlx_dyn_*() */
 #include "fopen.h" /* for curlx_f*() */
 #include "inet_ntop.h" /* for curlx_inet_ntop() */