Use forward declarations for octave_int<T> where possible (bug #59820). * liboctave/util/oct-inttypes-fwd.h: Forward declare template with correct visibility settings. * liboctave/array/idx-vector.h: Include header with complete declaration. * liboctave/util/oct-inttypes.h, libinterp/corefcn/mx-type-traits.h, libinterp/octave-value/ov-base-scalar.cc, libinterp/octave-value/ov-bool.cc, libinterp/octave-value/ov-float.cc, libinterp/octave-value/ov-magic-int.cc, libinterp/octave-value/ov-magic-int.h, libinterp/octave-value/ov-scalar.cc, liboctave/array/Array-i.cc, liboctave/array/MArray-i.cc, liboctave/numeric/sparse-dmsolve.cc, liboctave/operators/mx-inlines.cc: Include header with forward declaration.

--- a/liboctave/array/idx-vector.h	Sun Dec 05 10:52:55 2021 +0100
+++ b/liboctave/array/idx-vector.h	Sun Dec 05 11:23:41 2021 +0100
@@ -37,7 +37,7 @@
 
 #include "Array-fwd.h"
 #include "dim-vector.h"
-#include "oct-inttypes-fwd.h"
+#include "oct-inttypes.h"
 #include "oct-refcount.h"
 #include "Sparse-fwd.h"