cmake: set generation of libucs on windows mingw

it is needed to provide 'factory' symbol when compiling
dynamic library of verilog-a components
fix friend declaration with argument, violate spec

Build with lates clang++ 5.1 on OSX 10.9, the following error is reported.
The code in question violate C++ 11 spec, and clang is enforcing that rule.

C++11: §8.3.6.4 [dcl.fct.default]
"If a friend declaration specifies a default argument expression,
that declaration shall be a definition and shall be the only declaration
of the function or function template in the translation unit."
fix clang depracated finite

It has macros for isfinite, isnan, isinf.
\todo what about other platfoms, need to #define to std::
fix string format warging

format specifies type 'int' but the argument has type 'size_type'
remove generated data
Merge branch 'dynamic-loader-rebase140211' of https://github.com/guitorri/qucs into dynamic-loader-rebase140211
use isfinite, isnan, isinf from std::
Merge branch 'dynamic-loader-rebase140211' of https://github.com/guitorri/qucs into dynamic-loader-rebase140211
fix name of make, mingw32-make
cleanup va2cpp, cpp2lib, dyload working Win MinGW

Dynamic loader tested with MinGW 4.8.2, Windows 8.1 (64)
Tested with CMake, autotools need fix to emit aditional
library out of ucs.cpp. A --out-implib is needed to resolve
the factory symbols defined as external on the verilog-a dll.
fix friend declaration with argument, violate spec

Build with lates clang++ 5.1 on OSX 10.9, the following error is reported.
The code in question violate C++ 11 spec, and clang is enforcing that rule.

C++11: §8.3.6.4 [dcl.fct.default]
"If a friend declaration specifies a default argument expression,
that declaration shall be a definition and shall be the only declaration
of the function or function template in the translation unit."
fix clang depracated finite

It has macros for isfinite, isnan, isinf.
\todo what about other platfoms, need to #define to std::
fix string format warging

format specifies type 'int' but the argument has type 'size_type'
remove generated data
use isfinite, isnan, isinf from std::
fix name of make, mingw32-make
cleanup va2cpp, cpp2lib, dyload working Win MinGW

Dynamic loader tested with MinGW 4.8.2, Windows 8.1 (64)
Tested with CMake, autotools need fix to emit aditional
library out of ucs.cpp. A --out-implib is needed to resolve
the factory symbols defined as external on the verilog-a dll.
Merge branch 'dynamic-loader-rebase140211' of https://github.com/guitorri/qucs into dynamic-loader-rebase140211
oxs: fix va2cpp, cpp2lib
skip the build of qucs-filter-v2 on Darwin

The incomplete filter-v2 only builds withs -stdlib=libstc++
On OSX clang defaults to libstc++. \fixme