Add the isdnsync program which enable layer1 and layer2 on a card

this small tool is used to enable layer 1 and 2 on a given isdn card.
the card can be used to retrieve clock signal from a network. layer 2
(PTP) is required to keep layer 1 without interruption. this tool works
on e1 and s0 cards. to use the clock signal with other cards,
interconnection with a clock-slave-card is required.

(Andreas Eversberg)
diff --git a/src/Makefile.am b/src/Makefile.am
index 7fd7049..fbbbfdc 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,7 +1,7 @@
 INCLUDES = $(all_includes) -I$(top_srcdir)/include
 AM_CFLAGS=-Wall
 
-sbin_PROGRAMS = bsc_hack bs11_config ipaccess-find ipaccess-config
+sbin_PROGRAMS = bsc_hack bs11_config ipaccess-find ipaccess-config isdnsync
 noinst_LIBRARIES = libbsc.a libvty.a
 noinst_HEADERS = vty/cardshell.h
 
@@ -23,3 +23,5 @@
 
 ipaccess_config_SOURCES = ipaccess-config.c
 ipaccess_config_LDADD = libbsc.a libvty.a -ldl -ldbi $(LIBCRYPT)
+
+isdnsync_SOURCES = isdnsync.c