[PATCH] m4/ptyfuncs.m4 tools/configure: add linux headers for pty functions

[Florian Schmaus <flo@xxxxxxxxxxxx>]

To avoid implicit function declarations, which will cause an error on
modern compilers. See https://wiki.gentoo.org/wiki/Modern_C_porting

Downstream Gentoo bug: https://bugs.gentoo.org/904449

Signed-off-by: Florian Schmaus <flo@xxxxxxxxxxxx>
---
 m4/ptyfuncs.m4  | 3 +++
 tools/configure | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/m4/ptyfuncs.m4 b/m4/ptyfuncs.m4
index 3e37b5a23c8b..d1a2208398e3 100644
--- a/m4/ptyfuncs.m4
+++ b/m4/ptyfuncs.m4
@@ -19,6 +19,9 @@ AC_DEFUN([AX_CHECK_PTYFUNCS], [
             AC_LINK_IFELSE([AC_LANG_SOURCE([
 #ifdef INCLUDE_LIBUTIL_H
 #include INCLUDE_LIBUTIL_H
+#else
+#include <pty.h>
+#include <utmp.h>
 #endif
 int main(void) {
   openpty(0,0,0,0,0);
diff --git a/tools/configure b/tools/configure
index 5df30df9b35c..01f57b20c318 100755
--- a/tools/configure
+++ b/tools/configure
@@ -9002,6 +9002,9 @@ See \`config.log' for more details" "$LINENO" 5; }
 
 #ifdef INCLUDE_LIBUTIL_H
 #include INCLUDE_LIBUTIL_H
+#else
+#include <pty.h>
+#include <utmp.h>
 #endif
 int main(void) {
   openpty(0,0,0,0,0);
-- 
2.39.3