nss: Group merge does not react to ERANGE during merge (bug 33361)

The break statement in CHECK_MERGE is expected to exit the surrounding
while loop, not the do-while loop with in the macro.  Remove the
do-while loop from the macro.  It is not needed to turn the macro
expansion into a single statement due to the way CHECK_MERGE is used
(and the statement expression would cover this anyway).

Reviewed-by: Collin Funk <collin.funk1@gmail.com>
(cherry picked from commit 0fceed2545)

NEWS

@@ -41,6 +41,7 @@ The following bugs were resolved with this release:
   [33185] Fix double-free after allocation failure in regcomp
   [33234] Use TLS initial-exec model for __libc_tsd_CTYPE_* thread variables
   [33245] nptl: nptl: error in internal cancellation syscall handling
+  [33361] nss: Group merge does not react to ERANGE during merge
 
 Version 2.41
 

nss/getXXbyYY_r.c

@@ -157,19 +157,15 @@ __merge_einval (LOOKUP_TYPE *a,
 
 #define CHECK_MERGE(err, status)		\
   ({						\
-    do						\
+    if (err)					\
       {						\
-	if (err)				\
-	  {					\
-	    __set_errno (err);			\
-	    if (err == ERANGE)			\
-	      status = NSS_STATUS_TRYAGAIN;	\
-	    else				\
-	      status = NSS_STATUS_UNAVAIL;	\
-	    break;				\
-	  }					\
+	__set_errno (err);			\
+	if (err == ERANGE)			\
+	  status = NSS_STATUS_TRYAGAIN;		\
+	else					\
+	  status = NSS_STATUS_UNAVAIL;		\
+	break;					\
       }						\
-    while (0);					\
   })
 
 /* Type of the lookup function we need here.  */