+ revert changes to limit-checks from 20110122 (Debian #616711).
> minor type-cleanup of Ada95 binding (Nicolas Boulenguez):
+ corrected a minor sign error in a field of Low_Level_Field_Type, to
conform to form.h.
+ replaced C_Int by Curses_Bool as return type for some callbacks, see
fieldtype(3FORM).
+ modify samples/sample-explain.adb to provide explicit message when
explain.txt is not found.
+ improve makefiles for Ada95 tree (patch by Nicolas Boulenguez).
+ fix an off-by-one error in _nc_slk_initialize() from 20100605 fixes
for compiler warnings (report by Nicolas Boulenguez).
+ modify Ada95/gen/gen.c to declare unused bits in generated layouts,
needed to compile when chtype is 64-bits using gnat 4.4.5
