Cygwin: sys/cpuset.h: add cpuset-specific external functions

The latest incarnation of sys/cpuset.h broke building coreutils.
The reason is the inclusion of stdlib.h and string.h and hence
premature requests for datatypes not yet defined in the include
chain.

Avoid this by defining __cpuset_alloc and __cpuset_free as external
functions, now defined in sched.cc.  Linux is doing this too, just
using different names for the functions. Redefine  __cpuset_zero_s
to use __builtin_memset only on compilers supporting it, otherwise
using a simple loop. Drop the stdlib.h and string.h includes.

Fixes: 3f2790e044 ("Cygwin: Make gcc-specific code in <sys/cpuset.h> compiler-agnostic")
Reported-by: Denis Excoffier <cygwin@Denis-Excoffier.org>
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/cygwin.din

@@ -49,6 +49,8 @@ __b64_ntop NOSIGFE
 __b64_pton NOSIGFE
 __bsd_qsort_r NOSIGFE
 __chk_fail SIGFE
+__cpuset_alloc SIGFE
+__cpuset_free SIGFE
 __cxa_atexit = cygwin__cxa_atexit SIGFE
 __cxa_finalize SIGFE
 __dn_comp SIGFE

winsup/cygwin/include/sys/cpuset.h

@@ -9,8 +9,7 @@ details. */
 #ifndef _SYS_CPUSET_H_
 #define _SYS_CPUSET_H_
 
-#include <stdlib.h>
-#include <string.h>
+#include <sys/features.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -42,25 +41,23 @@ __cpuset_alloc_size (int num)
 }
 
 #define CPU_ALLOC(num) __cpuset_alloc (num)
-static __inline cpu_set_t *
-__cpuset_alloc (int num)
-{
-  return (cpu_set_t *) malloc (CPU_ALLOC_SIZE(num));
-}
+extern cpu_set_t * __cpuset_alloc (int);
 
 #define CPU_FREE(set) __cpuset_free (set)
-static __inline void
-__cpuset_free (cpu_set_t *set)
-{
-  free (set);
-}
+void __cpuset_free (cpu_set_t *);
 
 /* These _S macros operate on dynamically-sized cpu sets of size 'siz' bytes */
 #define CPU_ZERO_S(siz, set) __cpuset_zero_s (siz, set)
-static __inline void
+static __inline
 __cpuset_zero_s (size_t siz, cpu_set_t *set)
 {
-  (void) memset (set, 0, siz);
+#if __GNUC_PREREQ (2, 91)
+  __builtin_memset (set, 0, siz);
+#else
+  siz /= sizeof (__cpu_mask);
+  while (siz > 0)
+    set->_bits[--siz] = 0;
+#endif
 }
 
 #define CPU_SET_S(cpu, siz, set) __cpuset_set_s (cpu, siz, set)

winsup/cygwin/sched.cc

@@ -684,4 +684,16 @@ done:
   return 0;
 }
 
+cpu_set_t *
+__cpuset_alloc (int num)
+{
+  return (cpu_set_t *) malloc (CPU_ALLOC_SIZE(num));
+}
+
+void
+__cpuset_free (cpu_set_t *set)
+{
+  free (set);
+}
+
 } /* extern C */