configurator: Fix CTZ detection

The literal "1" in "1 << (sizeof(long{, long})*8 - 1)" should be 1L or
1LL, so that the expression has the right type. Otherwise, the shift
is only by 31 bits on x86 (other platforms may behave differently). To
avoid language lawyers shouting UB at me, and since
__builtin_ctz{,l,ll} formally takes unsigned parameters, use UL and
ULL suffixes.

Also, fix a typo (missing parenthesis) in the code for CTZLL causing
the detection of __builtin_ctzll to always fail for the wrong reason.

Signed-off-by: Rasmus Villemoes <rv@rasmusvillemoes.dk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>