move debug message

[ci skip]
Several autotools fixes for clang 3.4

* Tested clang 3.3 and clang 3.4 on Travis CI

* Tested locally on Mac OS 10.9.2, Xcode 5.1

* The issue was rooted in `AC_PROG_CXX(clang++ g++)` and the order of compiler setup.
  The x$GCC variable was so that flags were prepend to CXXFLAGS, some are unknown to Clang.
  Reordering the compiler tests and setting them properly seems to eliminate the issue.
fix bug 155

* split on filename underscore caused isses
use isfinite (C99) instead of finite

* Fix the following warning
  ~git/qucs/qucs/diagrams/curvediagram.cpp:69: warning: 'finite' is deprecated: first deprecated in OS X 10.9 [-Wdeprecated-declarations]
    if(finite(*px))

* see also:
  http://erlang.org/pipermail/erlang-patches/2013-November/004406.html