[klibc] Smart default for _KLIBC_NO_MMU
Assume we have an MMU if either sys_mmap or sys_mmap2 exist; otherwise not.
This can of course be overridden by <klibc/archconfig.h> still.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/include/klibc/sysconfig.h b/include/klibc/sysconfig.h
index c354b7c..48d62a4 100644
--- a/include/klibc/sysconfig.h
+++ b/include/klibc/sysconfig.h
@@ -25,9 +25,13 @@
* has no mmap(), munmap(), mremap(), msync(), mprotect(), or any
* of the mlock family.
*/
-/* Default to having an MMU */
+/* Default to having an MMU if we can find any mmap system call */
#ifndef _KLIBC_NO_MMU
-# define _KLIBC_NO_MMU 0
+# if defined(__NR_mmap) || defined(__NR_mmap2)
+# define _KLIBC_NO_MMU 0
+# else
+# define _KLIBC_NO_MMU 1
+# endif
#endif
