Comment # 3 on bug 1086297 from Petr Gajdos

Created attachment 779562 [details]
Test of days_since_1BC().

I will explain why t/base._calc_date_ymwd.t is failing, I have not looked on
other tests. The root of the issue lies in days_since_1BC(). Running `perl
test.pl`, I get on Tumbleweed:

x86_64

$ perl test.pl
YMD:  2009 8 15
D1BC: 733634
g = 733939
10000*733939 = 7339390000
y = 2009
YMD:  2009 8 15
$

i586

YMD:  2009 8 15
D1BC: 733634
g = 733939
10000*733939 = -1250544592
y = -342
YMD:  1997 2 2

Therefore, an integer overflow is the culprit.