When using ALSA or PortAudio, we need -ldl for XPBEEP

src/xpdev/Common.gmake

@@ -187,5 +187,13 @@ ifndef WITHOUT_PORTAUDIO
 
  ifneq ($(PORTAUDIO_PATH),NOTFOUND)
   XPDEV_CFLAGS += -DWITH_PORTAUDIO
+  ifeq ($(os),linux)
+   XPDEV-MT_LIBS += -ldl
+   XPDEV_LIBS += -ldl
+  endif
  endif
 endif
+ifeq ($(shell if [ -f /usr/include/alsa/asoundlib.h ] ; then echo YES ; fi),YES)
+ XPDEV-MT_LIBS += -ldl
+ XPDEV_LIBS += -ldl
+endif