maint: port to gcc -std=c99 -Wstrict-prototypes

This doesn’t fix any bugs, since the code is correct as-is on all
C versions.  However, it pacifies gcc -std=c99 -Wstrict-prototypes,
which complains about a function definition without arguments
unless there’s a previous prototype with ‘(void)’.
Most (but not all) of this patch merely reverts some recent
changes to be more consistent when porting to C23.
* dfltcc.c (is_dfltcc_enabled):
* gzip.c (get_input_size_and_time):
* inflate.c (inflate_stored, inflate_fixed, inflate_dynamic):
* unpack.c (read_byte):

1 files changed, 1 insertions, 1 deletions

diff --git a/gzip.c b/gzip.c
index 5cfdb24..9602271 100644
--- a/gzip.c
+++ b/gzip.c
@@ -710,7 +710,7 @@ input_eof ()
 }
 
 static void
-get_input_size_and_time ()
+get_input_size_and_time (void)
 {
   ifile_size = -1;
   time_stamp.tv_nsec = -1;