I'm not sure how (if) this helps but, with the same build of 64-bit Strawberry Perl-5.32.1 on Windows 7, this is what the same snippet of code outputs for me:
C:\_32\pscrpt\socket>perl try.pl
$gaiErr="The support for the specified socket type does not exist in t
+his address family. " (10044)
$osErr="Result too large" (34)
$extErr="The support for the specified socket type does not exist in t
+his address family" (10044)
No truncation of $gaiErr, a different $osErr, and effectively the same $extErr.
Cheers,
Rob