xalanc: fix Clang 19 and GCC 15 compat (#407880)

diff --git a/src/xalanc/XMLSupport/XalanOtherEncodingWriter.hpp b/src/xalanc/XMLSupport/XalanOtherEncodingWriter.hpp

index 8741cea49..075b1ad4f 100644

--- a/src/xalanc/XMLSupport/XalanOtherEncodingWriter.hpp

+++ b/src/xalanc/XMLSupport/XalanOtherEncodingWriter.hpp

@@ -301,43 +301,6 @@ public:

         return write(chars, start, length, m_charRefFunctor);

     }

-    void

-    writeSafe(

-            const XalanDOMChar*     theChars,

-            size_type               theLength)

-    {

-        for(size_type i = 0; i < theLength; ++i)

-        {

-            const XalanDOMChar  ch = theChars[i];

-

-            if (isUTF16HighSurrogate(ch) == true)

-            {

-                if (i + 1 >= theLength)

-                {

-                    throwInvalidUTF16SurrogateException(ch, 0,  getMemoryManager());

-                }

-                else 

-                {

-                    XalanUnicodeChar    value = decodeUTF16SurrogatePair(ch, theChars[i+1],  getMemoryManager());

-

-                    if (this->m_isPresentable(value))

-                    {

-                        write(value);

-                    }

-                    else

-                    {

-                        this->writeNumberedEntityReference(value);

-                    }

-

-                    ++i;

-                }

-            }

-            else

-            {

-                write(static_cast<XalanUnicodeChar>(ch));

-            }

-        }

-    }

     void

     write(const XalanDOMChar*     theChars)

    sha256 = "sha256:0q1204qk97i9h14vxxq7phcfpyiin0i1zzk74ixvg4wqy87b62s8";

  };

  patches = [

    # See https://github.com/llvm/llvm-project/issues/96859

    # xalan-c contains a templated code path that tries to access non-existent methods,

    # but before Clang 19 and GCC 15 this was no error as the template was never instantiated.

    # Note that the suggested fix of adding "-fdelayed-template-parsing"

    # to CXX_FLAGS would be sufficient for Clang 19, but as it would break again

    # once we upgrade to GCC 15, we remove the dead code entirely.

    ./0001-clang19-gcc15-compat.patch

  ];

  nativeBuildInputs = [ cmake ];

  buildInputs = [

    xercesc