In https://gcc.gnu.org/wiki/Visibility, they recommend _WIN32 and
__CYGWIN__ as the test defines for dllexport.
Also, logic is incorrect since HAVE_VISIBILITY can be defined but zero.
* libguile/scm.h (SCM_API): modify #ifdef logic
* libguile/continuations.h:
* libguile/continuations.c (scm_i_make_continuation): Refactor to expect
registers to already be captured.
* libguile/scm.h (scm_i_thread): Add forward decl.
* libguile/threads.h (struct scm_i_thread): Just fill in the struct
type.
* libguile/vm-engine.c (call/cc); Use the registers already captured
before entering the VM.
* libguile/scm.h (scm_tc7_values): New tc7. Never seen by Scheme, so we
don't need to update it anywhere else.
* libguile/values.h (scm_is_values): New public static inline function.
(scm_i_nvalues, scm_i_value_ref): New private static inline
functions.
(SCM_VALUESP): Use scm_is_value.
(scm_values_2, scm_values_3): New functions.
(scm_values_vtable): Remove; values objects are not structs any more.
* libguile/values.c (scm_i_extract_values_2): Adapt to new values
representation.
(print_values): Remove now-unused function.
(scm_c_nvalues): Use scm_i_nvalues.
(scm_c_value_ref): Use scm_i_value_ref.
(scm_values, scm_c_values): Make the new-style objects, which store
their values inline.
(scm_values_2, scm_values_3): New helpers, to avoid consing little
useless lists.
* libguile/vm-engine.c (halt, subr-call)
* libguile/eval.c (eval): Adapt to new values representation.
* libguile/i18n.c (scm_locale_string_to_integer)
(scm_locale_string_to_integer)
* libguile/numbers.c (scm_i_floor_divide, scm_i_ceiling_divide)
(scm_i_truncate_divide, scm_i_centered_divide, scm_i_round_divide)
(scm_i_exact_integer_sqrt)
* libguile/r6rs-ports.c (make_bytevector_output_port)
* libguile/srfi-1.c (scm_srfi1_partition, scm_srfi1_partition_x)
* libguile/srfi-14.c (scm_char_set_diff_plus_intersection)
(scm_char_set_diff_plus_intersection_x)
* libguile/posix.c (scm_getrlimit, scm_open_process): Adapt to use
scm_values_2 or scm_values_3.
* libguile/print.c (iprin1): Add printer for values objects.
As the FSF advises, 'There is no legal significance to using the
three-character sequence “(C)”, but it does no harm.' It does take up
space though! For that reason, we remove it here from our C files.