byte_conversion, bytscl and formats tests fail on Apple Silicon CI

[slayoo]

@gnudatalanguage/gdldevs, anyone having access to an Apple Silicon machine, help welcome! Thanks

Example output (https://github.com/gnudatalanguage/gdl/actions/runs/10431443505/job/28891119074)

66/214 Test  #66: test_byte_conversion.pro ...........***Failed    0.65 sec
...
% TEST_BYTE_BASIC_32768: Error on operation : input as Long for :       -32765
% TEST_BYTE_BASIC_32768: Error on operation : input as Long for :       -32766
% TEST_BYTE_BASIC_32768: Error on operation : input as Long for :       -32767
% TEST_BYTE_BASIC_32768: Error on operation : input as Long for :       -32769
% TEST_BYTE_BASIC_32768: Error on operation : input as Long for :       -32770
...

 67/214 Test  #67: test_bytscl.pro ....................***Failed    0.69 sec
...
% TEST_BYTSCL_TOP: Error on operation : Pb with top=     -128, min/max :        0,        0
...

102/214 Test #102: test_formats.pro ...................***Failed    1.13 sec
...
% When using the RAN1 mode, be sure to keep the RAN1 and dSFMT seed arrays in separate variables.
multiple reference file <<formats.GDL>> found ! First used !!
/Users/runner/work/gdl/build/testsuite/formats.GDL
/Users/runner/work/gdl/gdl/testsuite/formats.GDL
Files to be compared : formats.IDL, formats.GDL
...
% TEST_FORMATS: =  1595 errors encountered during TEST_FORMATS tests  =
...

The following tests FAILED:
	 66 - test_byte_conversion.pro (Failed)
	 67 - test_bytscl.pro (Failed)
	102 - test_formats.pro (Failed)

[alaingdl]

OK, but too much troubles on OSX now, I need some quiet time to investigate :(
(short answer : when compilating without the script, only test_formats is broken
--but I experienced glitches with the tests, I don't know why--
when compilating with the script, maybe due to wxwidget, everything is broken)

[GillesDuvert]

see #1881