installation error with libzrtpcpp-1.5.3

Hi - I got an error on the compile farm installing libzrtpcpp-1.5.3
(see http://chapters.gnu.org/~bjg/gsrc/summary/).  There is a
duplicate entry of ZrtpUserCallback.h in src/libzrtpcpp/Makefile.am
when CCRTP_SUPPORT is defined. The patch below gives a possible way to
fix it.

make[1]: Entering directory `/home/bjg/gsrc.main/gnu/zrtp/work/libzrtpcpp-1.5.3'
make -C work/libzrtpcpp-1.5.3   install DESTDIR=/home/bjg/gnu-packages/libzrtpcpp-1.5.3-DEST
test -z "/home/bjg/gnu/include/libzrtpcpp" || /bin/mkdir -p "/home/bjg/gnu-packages/libzrtpcpp-1.5.3-DEST/home/bjg/gnu/include/libzrtpcpp"
 /usr/bin/install -c -m 644 ZrtpCodes.h ZrtpCallback.h ZrtpUserCallback.h ZrtpConfigure.h ZrtpCWrapper.h ZrtpQueue.h ZrtpUserCallback.h zrtpccrtp.h TimeoutProvider.h '/home/bjg/gnu-packages/libzrtpcpp-1.5.3-DEST/home/bjg/gnu/include/libzrtpcpp'
/usr/bin/install: will not overwrite just-created `/home/bjg/gnu-packages/libzrtpcpp-1.5.3-DEST/home/bjg/gnu/include/libzrtpcpp/ZrtpUserCallback.h' with `ZrtpUserCallback.h'
make[4]: *** [install-zrtpincludeHEADERS] Error 1

(18:29)$ diff -u src/libzrtpcpp/Makefile.am.~1~ src/libzrtpcpp/Makefile.am
--- src/libzrtpcpp/Makefile.am.~1~              2010-12-05 18:17:43.000000000 +0000
+++ src/libzrtpcpp/Makefile.am                  2010-12-23 18:18:27.000000000 +0000
@@ -11,14 +11,14 @@
 AUTOMAKE_OPTIONS = no-dependencies dist-shar
 zrtpincludedir=$(includedir)/libzrtpcpp
 
+zrtpinclude_HEADERS = ZrtpCodes.h ZrtpCallback.h ZrtpUserCallback.h ZrtpConfigure.h ZrtpCWrapper.h
+
 if CCRTP_SUPPORT
 ccrtp_noinst = 
 ccrtp_inst = ZrtpQueue.h ZrtpUserCallback.h zrtpccrtp.h TimeoutProvider.h
+zrtpinclude_HEADERS += ZrtpQueue.h zrtpccrtp.h TimeoutProvider.h
 endif
 
-zrtpinclude_HEADERS = ZrtpCodes.h ZrtpCallback.h ZrtpUserCallback.h ZrtpConfigure.h ZrtpCWrapper.h $(ccrtp_inst)
-
-
 noinst_HEADERS =  Base32.h        ZrtpPacketBase.h      ZrtpPacketDHPart.h    ZrtpPacketHello.h \
                     ZIDFile.h       ZrtpPacketClearAck.h  ZrtpStateClass.h      ZrtpCrc32.h \
                                       ZIDRecord.h     ZrtpPacketCommit.h    ZrtpPacketGoClear.h   ZrtpStates.h \