[glibc] stdio-common: Restore while (1) loop in printf_positional

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b589bd672c529cf264dc6dfdfa11f73c7e4e1666

commit b589bd672c529cf264dc6dfdfa11f73c7e4e1666
Author: Florian Weimer <[email protected]>
Date:   Mon Aug 10 14:53:31 2026 +0200

    stdio-common: Restore while (1) loop in printf_positional
    
    The old condition is misleading because it is never evaluated.
    Switch back to the original approach before the printf buffer
    rewrite.

Diff:
---
 stdio-common/vfprintf-internal.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/stdio-common/vfprintf-internal.c b/stdio-common/vfprintf-internal.c
index 14ac0d9762..38a55443eb 100644
--- a/stdio-common/vfprintf-internal.c
+++ b/stdio-common/vfprintf-internal.c
@@ -1335,7 +1335,7 @@ printf_positional (struct Xprintf_buffer * buf, const CHAR_T *format,
 	}
 
       /* Process format specifiers.  */
-      do
+      while (1)
 	{
 # ifdef COMPILE_WPRINTF
 #  define CHECK_SPEC(spec) ((spec) <= UCHAR_MAX)
@@ -1415,7 +1415,6 @@ printf_positional (struct Xprintf_buffer * buf, const CHAR_T *format,
 	  }
 	  break;
 	}
-      while (Xprintf_buffer_has_failed (buf));
 
       /* Write the following constant string.  */
       Xprintf_buffer_write (buf,