Add missing include for libxml2 to gnucobol (#371974)

pkgs/by-name/gn/gnucobol/fix-libxml2-include.patch

@@ -0,0 +1,16 @@
+libcob: Fix include for xmlCleanupParser
+
+common.c uses xmlCleanupParser, which is defined in libxml/parser.h.
+---
+
+--- a/libcob/common.c	2025-01-01 03:03:49.762316279 +0100
++++ b/libcob/common.c	2025-01-01 03:01:56.632597306 +0100
+@@ -136,6 +136,7 @@
+ #if defined (WITH_XML2)
+ #include <libxml/xmlversion.h>
+ #include <libxml/xmlwriter.h>
++#include <libxml/parser.h>
+ #endif
+ 
+ #if defined (WITH_CJSON)
+

pkgs/by-name/gn/gnucobol/package.nix

@@ -63,6 +63,10 @@ stdenv.mkDerivation (finalAttrs: {
   # XXX: Without this, we get a cycle between bin and dev
   propagatedBuildOutputs = [ ];
 
+  patches = [
+    ./fix-libxml2-include.patch
+  ];
+
   # Skips a broken test
   postPatch = ''
     sed -i '/^AT_CHECK.*crud\.cob/i AT_SKIP_IF([true])' tests/testsuite.src/listings.at