utimecmp: avoid new GCC 7 warning from -Wbool-operation Testing this module would fail when using GCC 7 like this: $ CFLAGS='-O -Werror=bool-operation' ./gnulib-tool --create-testdir \ --dir=/tmp/x --with-tests --test utimecmp ../../gllib/utimecmp.c: In function ‘utimecmp’: ../../gllib/utimecmp.c:291:36: error: ‘~’ on a boolean expression \ [-Werror=bool-operation] time_t s = src_s & ~ (res == 2 * BILLION); ^ ../../gllib/utimecmp.c:370:16: error: ‘~’ on a boolean expression \ [-Werror=bool-operation] src_s &= ~ (res == 2 * BILLION); ^ * lib/utimecmp.c (utimecmp): Do not apply "~" to a boolean. Instead, make it explicit that we intend to apply it to 0 or 1.