Fix build with poppler-25.09.1, 25.10.0, 26.01.0 and 26.02.0.

Index: plug-ins/pdf/pdf-import.cpp
--- plug-ins/pdf/pdf-import.cpp.orig
+++ plug-ins/pdf/pdf-import.cpp
@@ -120,7 +120,7 @@ public :
     return FALSE;
   }
   //! Apparently no effect at all - so we translate everything to Dia space ouself
-  void setDefaultCTM(double *ctm)
+  void setDefaultCTM(std::array<double, 6> &ctm)
   {
     DiaMatrix mat;
 
@@ -396,7 +396,7 @@ public :
     if ((pf = strstr (family, " Oblique")) != NULL)
       *pf = 0;
 
-    const double *fm = f->getFontMatrix();
+    const std::array<double, 6> &fm = f->getFontMatrix();
     double fsize = state->getTransformedFontSize();
     if (fm[0] != 0)
       fsize *= fabs(fm[3] / fm[0]);
@@ -776,7 +776,7 @@ void
 DiaOutputDev::drawString(GfxState *state, GooString *s)
 {
   Color text_color = this->fill_color;
-  int len = s->getLength();
+  int len = s->size();
   DiaObject *obj;
   gchar *utf8 = NULL;
   DiaFont *font;
@@ -875,7 +875,7 @@ DiaOutputDev::drawImage (GfxState         *state,
   GdkPixbuf *pixbuf;
   Point pos;
   DiaObjectChange *change;
-  const double *ctm = state->getCTM();
+  const std::array<double, 6> &ctm = state->getCTM();
 
   pos.x = ctm[4] * scale;
   // there is some undocumented magic done with the ctm for drawImage
@@ -900,7 +900,7 @@ DiaOutputDev::drawImage (GfxState         *state,
       unsigned char *pixels = gdk_pixbuf_get_pixels (pixbuf);
       int y;
 
-      imgStr.reset(); // otherwise getLine() is crashing right away
+      imgStr.rewind(); // otherwise getLine() is crashing right away
       line = imgStr.getLine ();
       for (y = 0; y < height && line; ++y) {
 	unsigned char *dest = pixels + y * rowstride;
