tidy-up: misc

- lib1531: fix to use `curl_off_t`.
- src/tool_doswin: merge `_WIN32` guards.
- src/tool_doswin: limit `S_ISCHR()` to MS-DOS.
- src: dedupe `CURL_O_BINARY` macro into `tool_setup.h`.
- CMake/CurlTests.c: cleanup/formatting `HAVE_FILE_OFFSET_BITS` test.
- examples/httpput-postfields: delete unused include.
- spelling: MultiSSL.
- whitespace.

Ref: #15652
Closes #15799

src/tool_cb_wrt.c

@@ -39,11 +39,6 @@
 
 #include "memdebug.h" /* keep this as LAST include */
 
-#ifdef O_BINARY
-#define CURL_O_BINARY O_BINARY
-#else
-#define CURL_O_BINARY 0
-#endif
 #ifdef _WIN32
 #define OPENMODE S_IREAD | S_IWRITE
 #else

src/tool_doswin.c

@@ -45,8 +45,16 @@
 #ifdef _WIN32
 #  undef  PATH_MAX
 #  define PATH_MAX MAX_PATH
+
+#  define _use_lfn(f) (1)  /* long filenames always available */
+#elif !defined(__DJGPP__) || (__DJGPP__ < 2)  /* DJGPP 2.0 has _use_lfn() */
+#  define _use_lfn(f) (0)  /* long filenames never available */
+#elif defined(__DJGPP__)
+#  include <fcntl.h>       /* _use_lfn(f) prototype */
 #endif
 
+#ifdef MSDOS
+
 #ifndef S_ISCHR
 #  ifdef S_IFCHR
 #    define S_ISCHR(m) (((m) & S_IFMT) == S_IFCHR)
@@ -55,15 +63,6 @@
 #  endif
 #endif
 
-#ifdef _WIN32
-#  define _use_lfn(f) (1)   /* long filenames always available */
-#elif !defined(__DJGPP__) || (__DJGPP__ < 2)  /* DJGPP 2.0 has _use_lfn() */
-#  define _use_lfn(f) (0)  /* long filenames never available */
-#elif defined(__DJGPP__)
-#  include <fcntl.h>                /* _use_lfn(f) prototype */
-#endif
-
-#ifdef MSDOS
 /* only used by msdosify() */
 static SANITIZEcode truncate_dryrun(const char *path,
                                     const size_t truncate_pos);

src/tool_operate.c

@@ -111,14 +111,6 @@ extern const unsigned char curl_ca_embed[];
 #endif
 #endif
 
-/* 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
-#define CURL_O_BINARY O_BINARY
-#else
-#define CURL_O_BINARY 0
-#endif
-
 #ifndef SOL_IP
 #  define SOL_IP IPPROTO_IP
 #endif

src/tool_setup.h

@@ -66,6 +66,14 @@ extern FILE *tool_stderr;
 #  include "tool_strdup.h"
 #endif
 
+/* 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
+#define CURL_O_BINARY O_BINARY
+#else
+#define CURL_O_BINARY 0
+#endif
+
 #if defined(_WIN32)
 #  define CURL_STRICMP(p1, p2)  _stricmp(p1, p2)
 #elif defined(HAVE_STRCASECMP)