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));

Post on forum Encode.ru:
http://encode.ru/threads/1689-Google-Compress-Data-More-Densely-with-Zopfli?p=46476&viewfull=1#post46476

I additionally put binaries in FTP:
http://ftp.przemoc.net/pub/binaries/comp/pigz/

@przemoc thanks a lot! However it seems the program is not compiled with utf-8 arguments support, would this be possible?
e.g Описание.pdf returns: pigz.exe: skipping: ????????.pdf does not exist

commit 454c707ca233ee6ed64e51428be4ba6ea4296539
Author: Przemyslaw Pawelczyk <przemoc@gmail.com>
Date:   2018-02-17 13:26:30 +0100

    Create new patch for building pigz 2.4 on MSYS2+MinGW-w64.

@patroza Yeah, it is possible, but would require a bit more intrusive changes in the source code that I am willing to do right now.

@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.