prefer (X ? 1 : -1) when converting from boolean (1,0) to int (1,-1)

[pspp] / lib / xstrtoimax.c

#define __strtol strtoimax
#define __strtol_t intmax_t
#define __xstrtol xstrtoimax
#define STRTOL_T_MINIMUM INTMAX_MIN
#define STRTOL_T_MAXIMUM INTMAX_MAX
#include "xstrtol.c"