commit 953ceff17a4a15b10cfdd5edc3c8cae4884c8ec3

Author: Kamlesh Kumar <kamleshbhalui@gmail.com>

Date:   Thu Dec 5 16:49:00 2019 +0100

    <string.h>: Define __CORRECT_ISO_CPP_STRING_H_PROTO for Clang [BZ #25232]

    Without the asm redirects, strchr et al. are not const-correct.

    libc++ has a wrapper header that works with and without

    __CORRECT_ISO_CPP_STRING_H_PROTO (using a Clang extension).  But when

    Clang is used with libstdc++ or just C headers, the overloaded functions

    with the correct types are not declared.

    This change does not impact current GCC (with libstdc++ or libc++).

diff --git a/string/string.h b/string/string.h

index 73c22a535a..faf997b972 100644

--- a/string/string.h

+++ b/string/string.h

@@ -33,7 +33,8 @@ __BEGIN_DECLS

 #include <stddef.h>

 /* Tell the caller that we provide correct C++ prototypes.  */

-#if defined __cplusplus && __GNUC_PREREQ (4, 4)

+#if defined __cplusplus && (__GNUC_PREREQ (4, 4) \

+			    || __glibc_clang_prereq (3, 5))

 # define __CORRECT_ISO_CPP_STRING_H_PROTO

 #endif