examples: make them compile with compatibility functions disabled (Windows)

For MinGW this is `-DNO_OLDNAMES`, with MSVC it is
`-D_CRT_DECLARE_NONSTDC_NAMES=0`.

There have been some support for this before this patch.
After this patch this is extended to all examples.

(And also the standalone http/client programs, if here.)

Cherry-picked from #15652
Closes #15789

docs/examples/anyauthput.c

@@ -34,9 +34,11 @@
 #include <curl/curl.h>
 
 #ifdef _WIN32
-#  define FILENO(fp) _fileno(fp)
-#else
-#  define FILENO(fp) fileno(fp)
+#undef stat
+#define stat _stat
+#undef fstat
+#define fstat _fstat
+#define fileno _fileno
 #endif
 
 #if LIBCURL_VERSION_NUM < 0x070c03
@@ -98,7 +100,7 @@ int main(int argc, char **argv)
 
   /* get the file size of the local file */
   fp = fopen(file, "rb");
-  fstat(FILENO(fp), &file_info);
+  fstat(fileno(fp), &file_info);
 
   /* In Windows, this inits the Winsock stuff */
   curl_global_init(CURL_GLOBAL_ALL);

docs/examples/fileupload.c

@@ -30,6 +30,14 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 
+#ifdef _WIN32
+#undef stat
+#define stat _stat
+#undef fstat
+#define fstat _fstat
+#define fileno _fileno
+#endif
+
 int main(void)
 {
   CURL *curl;

docs/examples/ftpupload.c

@@ -31,6 +31,8 @@
 #include <errno.h>
 #ifdef _WIN32
 #include <io.h>
+#undef stat
+#define stat _stat
 #else
 #include <unistd.h>
 #endif

docs/examples/http2-upload.c

@@ -38,6 +38,11 @@
 #include <unistd.h>
 #endif
 
+#ifdef _WIN32
+#undef stat
+#define stat _stat
+#endif
+
 /* curl stuff */
 #include <curl/curl.h>
 #include <curl/mprintf.h>

docs/examples/httpput.c

@@ -30,6 +30,11 @@
 #include <sys/stat.h>
 #include <curl/curl.h>
 
+#ifdef _WIN32
+#undef stat
+#define stat _stat
+#endif
+
 /*
  * This example shows an HTTP PUT operation. PUTs a file given as a command
  * line argument to the URL also given on the command line.

tests/http/clients/hx-download.c

@@ -37,6 +37,10 @@
 #include <unistd.h>  /* getopt() */
 #endif
 
+#ifdef _WIN32
+#define strdup _strdup
+#endif
+
 #ifndef CURLPIPE_MULTIPLEX
 #error "too old libcurl, cannot do HTTP/2 server push!"
 #endif