Second try: we should add *flags for mozilla plugin not only in the case of xulrunner.

configure.ac

@@ -5149,20 +5149,21 @@ then
         have_xul=true
 	MOZILLA_CONFIG="${XULRUNNER_CONFIG}"
       fi
+    fi
     
-      if ${MOZILLA_CONFIG} --defines | grep -q 'MOZ_X11=1'; then
-        LDFLAGS="${LDFLAGS_save} ${X_LIBS} ${X_PRE_LIBS}"
-        AC_CHECK_LIB(Xt,XtStrings,
-         [
-	     VLC_ADD_CPPFLAGS([mozilla],[${X_CFLAGS}])
-	     VLC_ADD_LDFLAGS([mozilla],[${X_LIBS} ${X_PRE_LIBS} -lXt -lX11 -lSM -lICE])
-	 ],
-         [],
-         [[${X_LIBS} ${X_PRE_LIBS} -lX11 -lSM -lICE]
-        ])
-        LDFLAGS="${LDFLAGS_save}"
-      fi
+    if ${MOZILLA_CONFIG} --defines | grep -q 'MOZ_X11=1'; then
+      LDFLAGS="${LDFLAGS_save} ${X_LIBS} ${X_PRE_LIBS}"
+      AC_CHECK_LIB(Xt,XtStrings,
+       [
+         VLC_ADD_CPPFLAGS([mozilla],[${X_CFLAGS}])
+         VLC_ADD_LDFLAGS([mozilla],[${X_LIBS} ${X_PRE_LIBS} -lXt -lX11 -lSM -lICE])
+],
+       [],
+       [[${X_LIBS} ${X_PRE_LIBS} -lX11 -lSM -lICE]
+      ])
+      LDFLAGS="${LDFLAGS_save}"
     fi
+    
       mozilla=:
       dnl Workaround for http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=150490
       VLC_ADD_CPPFLAGS([mozilla],[[`${MOZILLA_CONFIG} --cflags plugin xpcom java | sed 's,-I\([^ ]*\)/mozilla/\([^ ]*\),-I\1/\2 -I\1/mozilla/\2,g' | xargs`]])