pkg/60152: graphics/xplot: configure from autoconf 2.13 uses implicit int

>Number:         60152
>Category:       pkg
>Synopsis:       graphics/xplot: configure from autoconf 2.13 uses implicit int
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Mar 31 22:30:00 +0000 2026
>Originator:     Robert Whitlock
>Release:        pkgsrc-2026Q1
>Organization:
>Environment:
NetBSD 11.99.5 amd64
>Description:
graphics/xplot is failing to build because its configure script uses implicit int in its test file for checking the C compiler. There are some other packages with the same problem, and so far it appears they all used autoconf 2.13. Presumably, my pkgsrc uses a newer GCC that has considered implicit int an error. I have not instructed pkgsrc to use a non-default compiler, however the bulk builds do not appear to be failing for some reason.
>How-To-Repeat:
cd graphics/xplot
make install
>Fix:
pkgsrc/graphics/xplot/patches/patch-configure:

$NetBSD$

--- configure.orig      2026-03-31 22:09:14.527655477 +0000
+++ configure
@@ -655,7 +655,7 @@ cat > conftest.$ac_ext << EOF
 #line 656 "configure"
 #include "confdefs.h"
 
-main(){return(0);}
+int main(){return(0);}
 EOF
 if { (eval echo configure:661: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   ac_cv_prog_cc_works=yes