glibmm compile tips

(1) g_assert was not declared in this scope

add #include
to 
convert.cc

exception.cc
error.cc
date.cc

https://community.ardour.org/node/1658

(2) g_date_set_time was not declared

change time -> time_t

http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=10;filename=glibmm2.4-set_time.diff;att=1;bug=359689

(3) propertyproxy_base.cc 

add 

#include

Then, I succeeded to copmile.