Move cpus_in_affinity_mask() to cpu-set-util.[ch]

It just seems to fit better there and it's always better to have things
in shared/ rather than basic/.

src/shared/condition.c

@@ -21,6 +21,7 @@
 #include "cap-list.h"
 #include "cgroup-util.h"
 #include "condition.h"
+#include "cpu-set-util.h"
 #include "efivars.h"
 #include "env-file.h"
 #include "extract-word.h"

src/shared/cpu-set-util.c

@@ -201,3 +201,37 @@ int parse_cpu_set_extend(
 
         return cpu_set_add_all(old, &cpuset);
 }
+
+int cpus_in_affinity_mask(void) {
+        size_t n = 16;
+        int r;
+
+        for (;;) {
+                cpu_set_t *c;
+
+                c = CPU_ALLOC(n);
+                if (!c)
+                        return -ENOMEM;
+
+                if (sched_getaffinity(0, CPU_ALLOC_SIZE(n), c) >= 0) {
+                        int k;
+
+                        k = CPU_COUNT_S(CPU_ALLOC_SIZE(n), c);
+                        CPU_FREE(c);
+
+                        if (k <= 0)
+                                return -EINVAL;
+
+                        return k;
+                }
+
+                r = -errno;
+                CPU_FREE(c);
+
+                if (r != -EINVAL)
+                        return r;
+                if (n > SIZE_MAX/2)
+                        return -ENOMEM;
+                n *= 2;
+        }
+}

src/shared/cpu-set-util.h

@@ -45,3 +45,5 @@ int parse_cpu_set_extend(
 static inline int parse_cpu_set(const char *rvalue, CPUSet *cpu_set){
         return parse_cpu_set_full(rvalue, cpu_set, false, NULL, NULL, 0, NULL);
 }
+
+int cpus_in_affinity_mask(void);