10880 posix_memalign() should avoid clobbering return parameter on failure

*** 22,34 ****
  /*
   * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
- #pragma ident   "%Z%%M% %I%     %E% SMI"
- 
  #include "lint.h"
  #include <stdlib.h>
  #include <errno.h>
  
  /*
   * SUSv3 - aligned memory allocation
--- 22,35 ----
  /*
   * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
  #include "lint.h"
+ 
+ #include <sys/sysmacros.h>
+ 
  #include <stdlib.h>
  #include <errno.h>
  
  /*
   * SUSv3 - aligned memory allocation
*** 47,64 ****
   */
  int
  posix_memalign(void **memptr, size_t alignment, size_t size)
  {
          void *ptr = NULL;
-         int error = 0;
- 
-         if (alignment == 0 ||
-             (alignment & (sizeof (void *) - 1)) != 0 ||
-             (alignment & (alignment - 1)) != 0)
-                 error = EINVAL;
-         else if (size != 0 &&
-             (ptr = memalign(alignment, size)) == NULL)
-                 error = ENOMEM;
  
          *memptr = ptr;
!         return (error);
  }
--- 48,68 ----
   */
  int
  posix_memalign(void **memptr, size_t alignment, size_t size)
  {
          void *ptr = NULL;
  
+         if ((alignment == 0) || !ISP2(alignment) ||
+             (alignment & (sizeof (void *) - 1)) != 0) {
+                 return (EINVAL);
+         } else if (size == 0) {
+                 *memptr = NULL;
+                 return (0);
+         } else {
+                 if ((ptr = memalign(alignment, size)) == NULL) {
+                         return (ENOMEM);
+                 } else {
                          *memptr = ptr;
!                         return (0);
!                 }
!         }
  }