Merged part of NetBSD pkgsrc patch-aj:

chunk 2:
-L/usr/lib is unnecessary

chunk 3:
Better DragonFly support.

configure.in

@@ -1590,7 +1590,7 @@ AC_HELP_STRING([--enable-pthread-sem], [use pthread semaphores [[default=yes]]])
             ;;
         *-*-netbsd*)
             pthread_cflags="-D_REENTRANT -D_THREAD_SAFE"
-            pthread_lib="-L/usr/lib -lpthread"
+            pthread_lib="-lpthread"
             ;;
         *-*-openbsd*)
             pthread_cflags="-D_REENTRANT"
@@ -1917,8 +1917,13 @@ CheckUSBHID()
               #if defined(HAVE_USB_H)
               #include <usb.h>
               #endif
+	      #ifdef __DragonFly__
+              #include <bus/usb/usb.h>
+              #include <bus/usb/usbhid.h>
+	      #else
               #include <dev/usb/usb.h>
               #include <dev/usb/usbhid.h>
+	      #endif
               #if defined(HAVE_USBHID_H)
               #include <usbhid.h>
               #elif defined(HAVE_LIBUSB_H)