[glibc] mtrace: Add attribute nocommon to mallwatch

[Tulio Magno Quites Machado Filho <tuliom@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=e766ce3088e1da976d6fa7903870683b3fed7f17

commit e766ce3088e1da976d6fa7903870683b3fed7f17
Author: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Date:   Fri Jul 2 18:12:13 2021 -0300

    mtrace: Add attribute nocommon to mallwatch
    
    Avoid compilation errors GCC versions that do not default to
    -fno-common, e.g. GCC <= 9.
    
    Fixes commit 00d28960c5388a582a0485e07629b553c32dde49 ("mtrace:
    Deprecate mallwatch and tr_break").
    
    Suggested-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
    Suggested-by: Florian Weimer <fweimer@redhat.com>

Diff:
---
 malloc/mtrace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/malloc/mtrace.c b/malloc/mtrace.c
index 6c2c58b706..f5b8321c6b 100644
--- a/malloc/mtrace.c
+++ b/malloc/mtrace.c
@@ -59,7 +59,7 @@ __libc_lock_define_initialized (static, lock);
    case some applications ended up linking against them but they don't actually
    do anything anymore; not that they did much before anyway.  */
 
-void *mallwatch;
+void *mallwatch __attribute__ ((nocommon));
 compat_symbol (libc, mallwatch, mallwatch, GLIBC_2_0);
 
 void