sprintf2.t: mark TODO bad denorm values under g++

Some t/op/sprintf2.t tests were failing under g++. This is due the perl
toker interpreting very small literal hex floating pointers as 0 rather
than as a subnormal value.

For example:

    perl -le'print "bad" if 0x1.fffffffffffffp-1022 == 0.0'

This breaks some of the sprintf2.t tests, so mark them TODO them if the
literal value evaluates to zero.

Note that this is a bug in the toker/g++/glibc rather than sprintf.

The issue is due to the use of pow() in scan_num():

under gcc and plain g++, pow(2.0, -1074) returns the smallest denorm
number; however, under 'g++ -ansi', it returns 0.0.

0 files changed, 0 insertions, 0 deletions