FMT_USE_NONTYPE_TEMPLATE_ARGS detection is wrong on trunk

[timsong-cpp]

With trunk GCC and -std=c++2c:

#include <fmt/compile.h>
using namespace fmt::literals;

int main() {
    fmt::print(""_cf);
}

does not compile with trunk fmt but does with 10.2.1:

https://gcc.godbolt.org/z/4WsvGP6bs

https://github.com/fmtlib/fmt/blob/aa52eb765dec0eb67fab4b035a4a05b82346c8f5/include/fmt/base.h#L143-L144 looks suspicious.

[vitaut]

Good catch, thanks! Looks like I accidentally inverted this check when cleaning it up.

[vitaut]

Fixed in #3937 (thanks @Arghnews).