diff --git a/src/compat/internal.h b/src/compat/internal.h
index 43ff62d..551212b 100644
--- a/src/compat/internal.h
+++ b/src/compat/internal.h
@@ -30,7 +30,15 @@
 #  undef _WIN32_WINNT
 #  define _WIN32_WINNT 0x0502
 #  include <windows.h>
+#  if defined(__MINGW32__) || defined(__MINGW64__)
+#   define off_t _off_t
+#   define off64_t _off64_t
+#  endif
 #  include <io.h>
+#  if defined(__MINGW32__) || defined(__MINGW64__)
+#   undef off_t
+#   undef off64_t
+#  endif
 #  include <fcntl.h>
 #  include <winnt.h>
 #  include <stdint.h>
diff --git a/src/compat/posix.h b/src/compat/posix.h
index 043562d..fc0e8d8 100644
--- a/src/compat/posix.h
+++ b/src/compat/posix.h
@@ -40,7 +40,15 @@
 #  define _POSIX_SOURCE 1
 #  define TMP_POSIX
 # endif
+# if defined(__MINGW32__) || defined(__MINGW64__)
+#  define off_t _off_t
+#  define off64_t _off64_t
+# endif
 # include <stdio.h>
+# if defined(__MINGW32__) || defined(__MINGW64__)
+#  undef off_t
+#  undef off64_t
+# endif
 # ifdef TMP_POSIX
 #  undef _POSIX_SOURCE
 #  undef TMP_POSIX