Workaround for buggy int64_T and uint64_T types under Windows with MATLAB < R2015b

This bug would impact the qmc_sequence MEX, which manipulates an int64
input/output argument (the seed). Thanks to little-endianness, the bug would
however only manifest for seeds > 2³¹.

mex/sources/dynmex.h

 /*
- * Copyright © 2009-2020 Dynare Team
+ * Copyright © 2009-2023 Dynare Team
  *
  * This file is part of Dynare.
  *
@@ -30,4 +30,18 @@
 # define mxIsScalar(x) (mxGetM(x) == 1 && mxGetN(x) == 1)
 #endif
 
+/* The int64_T and uint64_T type are broken under MinGW for MATLAB < R2015b
+   (they actually alias long integer types, which are 32-bit) */
+#if defined(MATLAB_MEX_FILE) && defined(__MINGW64__) && MATLAB_VERSION < 0x0806
+# define int64_T long long
+# define uint64_T unsigned long long
+#endif
+#ifdef __cplusplus
+static_assert(sizeof(int64_T) == 8, "The int64_T type is buggy");
+static_assert(sizeof(uint64_T) == 8, "The uint64_T type is buggy");
+#else
+_Static_assert(sizeof(int64_T) == 8, "The int64_T type is buggy");
+_Static_assert(sizeof(uint64_T) == 8, "The uint64_T type is buggy");
+#endif
+
 #endif