Make pigz.c compilable on MSYS2+MinGW-w64

pigz.c-msys2-mingw-w64.patch

Make pigz.c (2.4) compilable on MSYS2+MinGW-w64.

diff --git a/pigz.c b/pigz.c
index bbbfd2cd19a1..85a61eeca674 100644
--- a/pigz.c
+++ b/pigz.c
@@ -324,6 +324,11 @@
 // Use large file functions if available.
 #define _FILE_OFFSET_BITS 64
 
+#ifdef __MINGW32__
+/* Support 'j' length modifier (intmax_t) in printf(). */
+#define __USE_MINGW_ANSI_STDIO 1
+#endif
+
 // Included headers and what is expected from each.
 #include <stdio.h>      // fflush(), fprintf(), fputs(), getchar(), putc(),
                         // puts(), printf(), vasprintf(), stderr, EOF, NULL,
@@ -385,6 +390,15 @@
 #  define utimes(p,t)  0
 #  define lstat(p,s)   stat(p,s)
 #  define _exit(s)     exit(s)
+
+#define WINAPI __stdcall
+#define INVALID_HANDLE_VALUE ((HANDLE)-1)
+
+typedef void *HANDLE;
+typedef int BOOL;
+
+BOOL WINAPI FlushFileBuffers(HANDLE hFile);
+
 #endif
 
 #include "zlib.h"       // deflateInit2(), deflateReset(), deflate(),
@@ -3640,10 +3654,22 @@ local void touch(char *path, time_t t) {
 local void out_push(void) {
     if (g.outd == -1)
         return;
+#ifdef __MINGW32__
+    int ret = -1;
+    HANDLE h = (HANDLE)_get_osfhandle(g.outd);
+    if (h == INVALID_HANDLE_VALUE)
+        errno = EBADF;
+    else {
+        ret = -!FlushFileBuffers(h);
+        if (ret == -1)
+            errno = EINVAL;
+    }
+#else
 #ifdef F_FULLSYNC
     int ret = fcntl(g.outd, F_FULLSYNC);
 #else
     int ret = fsync(g.outd);
+#endif
 #endif
     if (ret == -1)
         throw(errno, "sync error on %s (%s)", g.outf, strerror(errno));

@przemoc and @patroza - I have created a fork that I think handles non-Latin filenames like Описание.pdf. I do not typically use Windows, and only use Latin characters in my own work, so I would be grateful for any advice.

By the way, I made my changes to for MSVC, and I do not have any experience with MINGW32. It is possible that a few changes of the ifdef clauses one could use wmain with MINGW32. If you implement this, I would like to know about it. My ultimate goal is a pull request to the main pigs repository that would provide robust support for Windows, and supporting both MINGW32 and MSVC would be fantastic.

Is it impossible to get this to work with the cygwin api's in mingw? Rather than introducing direct Windows API calls?