[PATCH 1/2] obstack: check def before use in macros

[Paul Eggert]

* lib/obstack.in.h (__attribute_noreturn__, __extension__):
Be more careful about checking whether a macro is defined before
using it, as some compilers complain otherwise.
Simplify the logic for __extension__.
---
 ChangeLog        |  8 ++++++++
 lib/obstack.in.h | 16 +++++++++-------
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index efb647b3ab..dc81c8c726 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2025-05-07  Paul Eggert  <egg...@cs.ucla.edu>
+
+       obstack: check def before use in macros
+       * lib/obstack.in.h (__attribute_noreturn__, __extension__):
+       Be more careful about checking whether a macro is defined before
+       using it, as some compilers complain otherwise.
+       Simplify the logic for __extension__.
+
 2025-05-07  Bruno Haible  <br...@clisp.org>
 
        Add/fix some license notices.
diff --git a/lib/obstack.in.h b/lib/obstack.in.h
index e361dc67ac..7d2327977e 100644
--- a/lib/obstack.in.h
+++ b/lib/obstack.in.h
@@ -176,7 +176,9 @@
 
 /* Not the same as _Noreturn, since it also works with function pointers.  */
 #ifndef __attribute_noreturn__
-# if 2 < __GNUC__ + (8 <= __GNUC_MINOR__) || defined __clang__ || 0x5110 <= 
__SUNPRO_C
+# if ((defined __GNUC__ && 2 < __GNUC__ + (8 <= __GNUC_MINOR__)) \
+      || defined __clang__ \
+      || (defined __SUNPRO_C && 0x5110 <= __SUNPRO_C))
 #  define __attribute_noreturn__ __attribute__ ((__noreturn__))
 # else
 #  define __attribute_noreturn__
@@ -329,9 +331,9 @@ extern int obstack_exit_failure;
 
 #define obstack_memory_used(h) _obstack_memory_used (h)
 
-#if defined __GNUC__ || defined __clang__
-# if ! (2 < __GNUC__ + (8 <= __GNUC_MINOR__) || defined __clang__ \
-        || 0x5150 <= __SUNPRO_C)
+#if (defined __GNUC__ || defined __clang__ \
+     || (defined __SUNPRO_C && 0x5150 <= __SUNPRO_C))
+# if defined __GNUC__ && ! (2 < __GNUC__ + (8 <= __GNUC_MINOR__))
 #  define __extension__
 # endif
 
@@ -481,7 +483,7 @@ extern int obstack_exit_failure;
        else                                                                  \
          __obstack_free (__o, __obj); })
 
-#else /* not __GNUC__ */
+#else /* not __GNUC__-like */
 
 # define obstack_object_size(h)                                                
      \
   ((_OBSTACK_SIZE_T) ((h)->next_free - (h)->object_base))
@@ -580,9 +582,9 @@ extern int obstack_exit_failure;
    (((h)->temp.tempptr > (void *) (h)->chunk                                 \
      && (h)->temp.tempptr < (void *) (h)->chunk_limit)                       \
     ? (void) ((h)->next_free = (h)->object_base = (char *) (h)->temp.tempptr) \
-    : __obstack_free (h, (h)->temp.tempptr)))
+    : __obstack_free ((h), (h)->temp.tempptr)))
 
-#endif /* not __GNUC__ */
+#endif /* not __GNUC__-like */
 
 #ifdef __cplusplus
 }       /* C++ */
-- 
2.49.0