because:
- Constructing fp numbers isn't quite trivial
- 3 additional calls to strchr per number is noticeable slow
Also: exclude abitest.c:ret_longdouble_test2 on _WIN32
for mixed gcc/tcc scenario
test case:
- make -k test (on win32):
-2.120000 0.500000 23000000000.000000
+2.120000 0.500000 22999999999.999996
...
ret_longdouble_test2... failure
This reverts 857f7dbfa6
and deaee6c249
899d26605c