Use long long offsets for MinGW.
diff --git a/zconf.h b/zconf.h
index fbe7a79..ea3b6d6 100644
--- a/zconf.h
+++ b/zconf.h
@@ -511,6 +511,8 @@
#if !defined(_WIN32) && defined(Z_LARGE64)
# define z_off64_t off64_t
+#elif defined(__MINGW32__)
+# define z_off64_t long long
#elif defined(_WIN32) && !defined(__GNUC__)
# define z_off64_t __int64
#elif defined(__GO32__)
diff --git a/zconf.h.cmakein b/zconf.h.cmakein
index 96e9296..0eced14 100644
--- a/zconf.h.cmakein
+++ b/zconf.h.cmakein
@@ -513,6 +513,8 @@
#if !defined(_WIN32) && defined(Z_LARGE64)
# define z_off64_t off64_t
+#elif defined(__MINGW32__)
+# define z_off64_t long long
#elif defined(_WIN32) && !defined(__GNUC__)
# define z_off64_t __int64
#elif defined(__GO32__)
diff --git a/zconf.h.in b/zconf.h.in
index fbe7a79..ea3b6d6 100644
--- a/zconf.h.in
+++ b/zconf.h.in
@@ -511,6 +511,8 @@
#if !defined(_WIN32) && defined(Z_LARGE64)
# define z_off64_t off64_t
+#elif defined(__MINGW32__)
+# define z_off64_t long long
#elif defined(_WIN32) && !defined(__GNUC__)
# define z_off64_t __int64
#elif defined(__GO32__)