gnu: ploticus: Fix build with GCC 14.

* gnu/packages/patches/ploticus-pointer-types.patch: New file.
* gnu/packages/plotutils.scm (ploticus)[source]: Use it.
* gnu/local.mk (dist_patch_DATA): Add it.

Fixes: guix/guix#1818
Change-Id: I121ca003c9fecc916580e4c949706e853ea74ec7
Signed-off-by: Andreas Enge <andreas@enge.fr>

gnu/local.mk

@@ -2119,6 +2119,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/plink-endian-detection.patch		\
   %D%/packages/patches/plib-CVE-2011-4620.patch		\
   %D%/packages/patches/plib-CVE-2012-4552.patch		\
+  %D%/packages/patches/ploticus-pointer-types.patch		\
   %D%/packages/patches/plotutils-spline-test.patch		\
   %D%/packages/patches/polkit-disable-systemd.patch		\
   %D%/packages/patches/portaudio-audacity-compat.patch		\

gnu/packages/patches/ploticus-pointer-types.patch

@@ -0,0 +1,31 @@
+From <https://sources.debian.org/data/main/p/ploticus/2.42-8/debian/patches/fix-ftbfs-gcc14.patch>.
+
+Fixes a build error with GCC 14:
+
+  svg.c: In function ‘PLGS_trailer’:
+  svg.c:743:46: error: passing argument 1 of ‘gzprintf’ from incompatible pointer type [-Wincompatible-pointer-types]
+    743 |                 if( svg_compress ) gzprintf( outfp, "%s", buf );
+	|                                              ^~~~~
+	|                                              |
+	|                                              FILE *
+
+--- a/src/svg.c
++++ b/src/svg.c
+@@ -740,7 +740,7 @@
+ 	buf = svg_style; /* reuse */
+ 	while( fgets( buf, 999, svg_fp ) != NULL ) {
+ #ifdef WZ
+-		if( svg_compress ) gzprintf( outfp, "%s", buf ); 
++		if( svg_compress ) gzprintf( (gzFile) outfp, "%s", buf ); 
+ 		else 
+ #endif
+ 			printf( "%s", buf );
+@@ -749,7 +749,7 @@
+ 	unlink( svg_tmpfilename );
+ #ifdef WZ
+ 	if( svg_compress && !svg_stdout ) {
+-		gzclose( outfp );
++		gzclose( (gzFile) outfp );
+ 		chmod( svg_filename, 00644 );
+ 		}
+ #endif

gnu/packages/plotutils.scm

@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013-2021, 2025 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2015 Eric Bavier <bavier@member.fsf.org>
 ;;; Copyright © 2016-2025 Nicolas Goaziou <mail@nicolasgoaziou.fr>
 ;;; Copyright © 2018 Tobias Geerinckx-Rice <me@tobias.gr>
@@ -305,6 +305,7 @@ went to university in the 1990s, this is the library for you.")
                (base32
                 "1c70cvfvgjh83hj1x21130wb9qfr2rc0x47cxy9kl805yjwy8a9z"))
               (modules '((guix build utils)))
+              (patches (search-patches "ploticus-pointer-types.patch"))
               (snippet
                ;; Install binaries in the right place.
                #~(begin