_SC_PAGESIZE is standard. Some ancient legacy unix variants used _SC_PAGE_SIZE

instead, but we are not such a system and should not propagate such things.

libc/stdlib/malloc-standard/malloc.h

@@ -136,7 +136,7 @@ extern pthread_mutex_t __malloc_lock;
 */
 #ifndef malloc_getpagesize
 #  include <unistd.h>
-#  define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
+#  define malloc_getpagesize sysconf(_SC_PAGESIZE)
 #else /* just guess */
 #  define malloc_getpagesize (4096)
 #endif