[glibc/azanella/clang] Disable __USE_EXTERN_INLINES for clang

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=91a93b8f5ce0501b54d48f7d1efe1f8c4e0a177c

commit 91a93b8f5ce0501b54d48f7d1efe1f8c4e0a177c
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 d92503dfed..23e29b9f4d 100644
--- a/include/features.h
+++ b/include/features.h
@@ -523,7 +523,7 @@
 /* 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