enforsed compilation with -W -Werror

asn1c/tests/check-22.c

asn1c/tests/check-24.c

asn1c/tests/check-25.c

asn1c/tests/check-30.c

asn1c/tests/check-31.c

asn1c/tests/check-32.c

asn1c/tests/check-33.c

asn1c/tests/check-35.c

asn1c/tests/check-41.c

asn1c/tests/check-43.c

libasn1compiler/asn1c_misc.c

libasn1compiler/asn1c_save.c

libasn1compiler/asn1compiler.c

libasn1fix/asn1fix_class.c

libasn1fix/asn1fix_integer.c

libasn1fix/asn1fix_misc.c

libasn1parser/asn1p_expr_str.h

libasn1parser/asn1p_ref.c

libasn1print/asn1print.c

skeletons/BIT_STRING.c