Update configure scripts

Add --extra-cflags as config parameter for user defined extra CFLAGS.
Add -g to asflags when debug enabled for arm targets.

Change-Id: Ibdde7cfdda6736c1c1db45e6466bd08504a51f15
diff --git a/configure b/configure
index 5a502ae..cb568d7 100755
--- a/configure
+++ b/configure
@@ -300,7 +300,7 @@
         optval="${opt#*=}"
         case "$opt" in
         --disable-codecs) for c in ${CODECS}; do disable $c; done ;;
-        *) process_common_cmdline $opt
+        *) process_common_cmdline "$opt"
         ;;
         esac
     done