awk: use "long long" as integer type, not "int"

awk: use "long long" as integer type, not "int"

Testcase:
awk "BEGIN{n=(2^31)-1; print n, int(n), n%1, ++n, int(n), n%1}"
2147483647 2147483647 0 2147483648 2147483648 0

(last three values weren't showing right)

function                                             old     new   delta
evaluate                                            3444    3458     +14
fmt_num                                              221     230      +9

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>