<sys/cdefs.h>: Inhibit macro expansion for __glibc_has_include

This is currently ineffective with GCC because of GCC PR 80005, but
it makes sense to anticipate a fix for this defect.

Suggested by Zack Weinberg.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

2 files changed, 9 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index fc12a3e..4aae5e7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2019-06-14  Florian Weimer  <fweimer@redhat.com>
+
+	* misc/sys/cdefs.h (__glibc_has_include): Do not use a
+	function-like macro, so that __has_include can inhibit expansion
+	of its argument.
+
 2019-06-13  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/unix/sysv/linux/bits/in.h (IPV6_ROUTER_ALERT_ISOLATE):
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 638872b..f1bd994 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -413,7 +413,9 @@
 #endif
 
 #ifdef __has_include
-# define __glibc_has_include(header)	__has_include (header)
+/* Do not use a function-like macro, so that __has_include can inhibit
+   macro expansion.  */
+# define __glibc_has_include __has_include
 #else
 # define __glibc_has_include(header)	0
 #endif