C99 is now the C standard for all our C code.

The main new feature is mixed variable declarations and code, which can help
reduce uninitialized variables or accidental variable reuse.

Due to incomplete C99 support in VS 2013, variable length arrays are not
supported, BLI_array_alloca must still be used. The header <tgmath.h> is also
not supported.

Differential Revision: https://developer.blender.org/D1631

source/blender/python/mathutils/mathutils_Matrix.c

@@ -2055,7 +2055,7 @@ static PyObject *Matrix_richcmpr(PyObject *a, PyObject *b, int op)
 
 static Py_hash_t Matrix_hash(MatrixObject *self)
 {
-	float mat[SQUARE(MATRIX_MAX_DIM)];
+	float mat[MATRIX_MAX_DIM * MATRIX_MAX_DIM];
 
 	if (BaseMath_ReadCallback(self) == -1)
 		return -1;