* lib/obstack.in.h (PTR_INT_TYPE): Define, for compatibility
with glibc even though we don’t need the type for anything
other than compatibility. Include stddef.h only if needed,
like glibc obstack.h does.
---
ChangeLog | 6 ++++++
lib/obstack.in.h | 15 +++++++++++++--
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 5c78f4dac4..7448c09ebc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2025-05-05 Paul Eggert <egg...@cs.ucla.edu>
+ obstack: define PTR_INT_TYPE
+ * lib/obstack.in.h (PTR_INT_TYPE): Define, for compatibility
+ with glibc even though we don’t need the type for anything
+ other than compatibility. Include stddef.h only if needed,
+ like glibc obstack.h does.
+
obstack: merge better with glibc
When compiled for glibc, keep the fake array content size at 4,
for API compatibility with older glibc.
diff --git a/lib/obstack.in.h b/lib/obstack.in.h
index c82f6d4a6c..6b51ebde5d 100644
--- a/lib/obstack.in.h
+++ b/lib/obstack.in.h
@@ -113,9 +113,20 @@
# endif
#endif
-#include <stddef.h> /* For size_t and ptrdiff_t. */
+/* For backward compatibility with older glibc,
+ define the otherwise-unused macro PTR_INT_TYPE. If __PTRDIFF_TYPE__ is
+ defined, as with GNU C, use that; that way we don't pollute the
+ namespace with <stddef.h>'s symbols. Otherwise, include <stddef.h>
+ and use ptrdiff_t. */
+#ifdef __PTRDIFF_TYPE__
+# define PTR_INT_TYPE __PTRDIFF_TYPE__
+#else
+# include <stddef.h>
+# define PTR_INT_TYPE ptrdiff_t
+#endif
+
#include <stdint.h> /* For uintptr_t. */
-#include <string.h> /* For memcpy. */
+#include <string.h> /* For memcpy, size_t. */
/* These macros highlight the places where this implementation
is different from the one in GNU libc. */
--
2.49.0
