int cpuset_set(cpuid_t cpu, cpuset_t *set);
                ^~~~~~~
                uid_t
./compat/cpuset.h:66:16: error: unknown type name 'cpuid_t'; did you mean 'uid_t'?
 int cpuset_clr(cpuid_t cpu, cpuset_t *set);
                ^~~~~~~
                uid_t
./compat/cpuset.h:70:18: error: unknown type name 'cpuid_t'; did you mean 'uid_t'?
 int cpuset_isset(cpuid_t cpu, const cpuset_t *set);
                  ^~~~~~~
                  uid_t
*** Error code 1

% grep -IR cpu_set_t /usr/include
/usr/include/sched.h:typedef	cpumask_t		cpu_set_t;
...

/*
 * cpumask_t - a mask representing a set of cpus and supporting routines.
 *
 * WARNING! It is recommended that this mask NOT be made variably-sized
 *	    because it affects a huge number of system structures.  However,
 *	    kernel code (non-module) can be optimized to not operate on the
 *	    whole mask.
 */
#define _CPUMASK_ELEMENTS	4	/* tested by assembly for #error */
typedef struct {
	__uint64_t      ary[4];
} cpumask_t;

% gcc -dM -E - < /dev/null | sort | grep -i -E 'linux|bsd|gnu|linux|dragon|i*86|amd'
#define __DragonFly__ 1
#define __GNUC_MINOR__ 3
#define __GNUC_PATCHLEVEL__ 0
#define __GNUC_STDC_INLINE__ 1
#define __GNUC__ 8
#define __VERSION__ "8.3 [DragonFly] Release/2019-02-22"
#define __amd64 1
#define __amd64__ 1
#define __x86_64 1
#define __x86_64__ 1