Peter M. Groen / libmodbus

Thanks Tobias Doerffel.

It will better to code something such as:
https://github.com/crossroads-io/libxs/blob/master/src/err.cpp

I don't intend to rewrite glib neither :(

Thanks Giampaolo Bellini.

- depends of automake 1.11
- C99
- pic-only
- more warning C flags
- remove obscure checks
- don't print directories
- add libmodbus.pc to clean files
- remove -Werror

Add standalone Makefiles for the modbus DLL and tests, using the modbus DLL.

Thanks to Denis Davydov

Fix EXXX values defined in Microsoft C Runtime 10

Thanks to Carlos Tangerino

Thanks to oldfaber

Thanks to oldfaber.

Original patch provided by Michael Haberler <git@mah.priv.at>.

Thanks to Stefan Finzel for the bug report

Signed-off-by: Michael Heimpold <mhei@heimpold.de>

Thanks to Thomas Stalder and Torello Querci for the report.

Original patch for new connect function by Thomas Stalder.