Fix build with poppler-25.09.1.

From upstream commit b60d81745016b5f20d4c6aec6d073b8a6f3e499c.

Index: src/extension/internal/pdfinput/svg-builder.cpp
--- src/extension/internal/pdfinput/svg-builder.cpp.orig
+++ src/extension/internal/pdfinput/svg-builder.cpp
@@ -1025,7 +1025,7 @@ gchar *SvgBuilder::_createTilingPattern(GfxTilingPatte
     pattern_node->setAttribute("patternUnits", "userSpaceOnUse");
     // Set pattern tiling
     // FIXME: don't ignore XStep and YStep
-    const double *bbox = tiling_pattern->getBBox();
+    const auto& bbox = tiling_pattern->getBBox();
     pattern_node->setAttributeSvgDouble("x", 0.0);
     pattern_node->setAttributeSvgDouble("y", 0.0);
     pattern_node->setAttributeSvgDouble("width", bbox[2] - bbox[0]);
@@ -1255,7 +1255,7 @@ void SvgBuilder::updateFont(GfxState *state, std::shar
 
     auto new_font_size = state->getFontSize();
     if (font->getType() == fontType3) {
-        const double *font_matrix = font->getFontMatrix();
+        const auto& font_matrix = font->getFontMatrix();
         if (font_matrix[0] != 0.0) {
             new_font_size *= font_matrix[3] / font_matrix[0];
         }
