Implemented ticket #1038: null audio device

 * pjmedia-audiodev:
   * implement null audio device
 * build:
   * added null audio support on MMP, and Makefile (TODO: vs6 and vs2005)



git-svn-id: https://svn.pjsip.org/repos/pjproject/trunk@3102 74dad513-b988-da41-8d7b-12977e46ad98
diff --git a/build.symbian/pjmedia_audiodev.mmp b/build.symbian/pjmedia_audiodev.mmp
index f4e25d2..a80cfeb 100644
--- a/build.symbian/pjmedia_audiodev.mmp
+++ b/build.symbian/pjmedia_audiodev.mmp
@@ -17,6 +17,7 @@
 SOURCE		symb_aps_dev.cpp
 SOURCE		symb_mda_dev.cpp
 SOURCE		symb_vas_dev.cpp
+SOURCE		null_dev.c
 
 SYSTEMINCLUDE	..\pjmedia\include
 SYSTEMINCLUDE	..\pjlib\include