This commit makes the code (mostly) C99-compatible, enabling to compile
it without the -Wno-error=implicit-function-declaration flag. This
way, Magic becomes usable on arm64 architectures, specifically on Apple
computers with M1/M2 SoC.
Compression levels of the output can be controlled with the "gds
compress [<value>]" command, where <value> 0 (default) is uncompressed
output, 6 is "normal" gzip compression, and 9 is maximum compression.
behavior, in which all cells read from GDS are given a zero
timestamp, and the timestamp is set when the file is written to
disk, the default behavior now is to set the layout cell's timestamp
from the timestamp provided in the GDS (the creation date timestamp,
specifically). The same command "gds datestamp" implemented in the
previous commit for GDS writes now also applies to GDS reads: If
set to "no", then the timestamp value from the GDS file is
transferred to the layout view (default behavior); if set to "yes",
then the timestamp is set to zero (legacy behavior). If set to
a value, then the value is used as the timestamp.
Alessandro De Laurenzis
Tim Edwards