[glibc/azanella/clang] Disable __USE_EXTERN_INLINES for clang

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=6e102459e53135b42d7d6c16b2b87778f1c620ab

commit 6e102459e53135b42d7d6c16b2b87778f1c620ab
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Thu Oct 7 18:16:04 2021 -0700

    Disable __USE_EXTERN_INLINES for clang
    
    clang does not allow to redefine attributes after function declaration.
    Although it work for external usage, its breaks the build for internal
    symbol that glibc provides as optimization (for instance bsearch
    with stdlib-bsearch.h or __cmsg_nxthdr).
    
    Disable such optimization for clang while building glibc.

Diff:
---
 include/features.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/features.h b/include/features.h
index 7c51b4a2e4..a94fc1b3a4 100644
--- a/include/features.h
+++ b/include/features.h
@@ -515,7 +515,7 @@
 /* Decide whether we can define 'extern inline' functions in headers.  */
 #if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
     && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__ \
-    && defined __extern_inline
+    && defined __extern_inline && !(defined __clang__ && defined _LIBC)
 # define __USE_EXTERN_INLINES	1
 #endif