ChangeLog
2020-09-24  Tim Rice  <tim@multitalents.net>
	* m4/fbufmode.m4: add AC_CHECK_HEADERS_ONCE([stdio_ext.h])
	* m4/fpurge.m4: Likewise.
	* m4/freadable.m4: Likewise.
	* m4/freadahead.m4: Likewise.
	* m4/freading.m4: Likewise.
	* m4/freadptr.m4: Likewise.
	* m4/fseterr.m4: Likewise.
	* m4/fwritable.m4: Likewise.
	* m4/fwriting.m4: Likewise.

diff --git a/m4/fbufmode.m4 b/m4/fbufmode.m4
index 87e76e0d7..99f835e5e 100644
--- a/m4/fbufmode.m4
+++ b/m4/fbufmode.m4
@@ -6,6 +6,7 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_FBUFMODE],
 [
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
   dnl Prerequisites of lib/fbufmode.c.
   AC_CHECK_FUNCS_ONCE([__flbf __fbufsize])
 ])
diff --git a/m4/fpurge.m4 b/m4/fpurge.m4
index 0796a6f0e..6bc3c937a 100644
--- a/m4/fpurge.m4
+++ b/m4/fpurge.m4
@@ -8,6 +8,7 @@ AC_DEFUN([gl_FUNC_FPURGE],
 [
   AC_REQUIRE([gl_STDIO_H_DEFAULTS])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
   AC_CHECK_FUNCS_ONCE([fpurge])
   AC_CHECK_FUNCS_ONCE([__fpurge])
   AC_CHECK_DECLS([fpurge], , , [[#include <stdio.h>]])
diff --git a/m4/freadable.m4 b/m4/freadable.m4
index 3237effe0..e5a317ee8 100644
--- a/m4/freadable.m4
+++ b/m4/freadable.m4
@@ -6,5 +6,6 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_FREADABLE],
 [
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
   AC_CHECK_FUNCS_ONCE([__freadable])
 ])
diff --git a/m4/freadahead.m4 b/m4/freadahead.m4
index 05132b526..5d2d9af87 100644
--- a/m4/freadahead.m4
+++ b/m4/freadahead.m4
@@ -6,5 +6,6 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_FREADAHEAD],
 [
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
   AC_CHECK_FUNCS_ONCE([__freadahead])
 ])
diff --git a/m4/freading.m4 b/m4/freading.m4
index 440c241e4..10ad2349f 100644
--- a/m4/freading.m4
+++ b/m4/freading.m4
@@ -6,5 +6,6 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_FREADING],
 [
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
   AC_CHECK_FUNCS_ONCE([__freading])
 ])
diff --git a/m4/freadptr.m4 b/m4/freadptr.m4
index 799703554..88f4965e3 100644
--- a/m4/freadptr.m4
+++ b/m4/freadptr.m4
@@ -6,5 +6,6 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_FREADPTR],
 [
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
   AC_CHECK_FUNCS_ONCE([__freadptr])
 ])
diff --git a/m4/fseterr.m4 b/m4/fseterr.m4
index 7266579b3..64036790f 100644
--- a/m4/fseterr.m4
+++ b/m4/fseterr.m4
@@ -6,5 +6,6 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_FSETERR],
 [
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
   AC_CHECK_FUNCS_ONCE([__fseterr])
 ])
diff --git a/m4/fwritable.m4 b/m4/fwritable.m4
index dbe887e88..ac5d71eb4 100644
--- a/m4/fwritable.m4
+++ b/m4/fwritable.m4
@@ -6,5 +6,6 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_FWRITABLE],
 [
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
   AC_CHECK_FUNCS_ONCE([__fwritable])
 ])
diff --git a/m4/fwriting.m4 b/m4/fwriting.m4
index 4d7cd3ede..a87f35986 100644
--- a/m4/fwriting.m4
+++ b/m4/fwriting.m4
@@ -6,5 +6,6 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_FWRITING],
 [
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
   AC_CHECK_FUNCS_ONCE([__fwriting])
 ])