Copied from Debian.

2017-06-14  Florian Weimer  <fweimer@redhat.com>

	* sysdeps/i386/i686/multiarch/strcspn-c.c: Add IS_IN (libc) guard.
	* sysdeps/i386/i686/multiarch/varshift.c: Likewise.

--- a/sysdeps/i386/i686/multiarch/strcspn-c.c
+++ b/sysdeps/i386/i686/multiarch/strcspn-c.c
@@ -1,2 +1,4 @@
-#define __strcspn_sse2 __strcspn_ia32
-#include <sysdeps/x86_64/multiarch/strcspn-c.c>
+#if IS_IN (libc)
+# define __strcspn_sse2 __strcspn_ia32
+# include <sysdeps/x86_64/multiarch/strcspn-c.c>
+#endif
--- a/sysdeps/i386/i686/multiarch/varshift.c
+++ b/sysdeps/i386/i686/multiarch/varshift.c
@@ -1 +1,3 @@
-#include <sysdeps/x86_64/multiarch/varshift.c>
+#if IS_IN (libc)
+# include <sysdeps/x86_64/multiarch/varshift.c>
+#endif