Update to support MSYS2/GCC

[jalius]

Adding build support for MSYS2/GCC and cleaning up some various build errors.

• Fix implementation of osal_thread_create() to match declaration.
• Fix missing timezone struct declaration.
• Add GCC style struct packing
• Update CMakeLists with non-MSVC win32 build instructions
• Address some compiler warnings arising from unused parameters and variables.
• Remove stdint.h and inttypes.h which are MSVC specific. The compiler should find these standard library files based on the target rather than including them in the project.

It now builds properly on MSYS2/GCC using cmake generators "MSYS Makefiles" and "Ninja".

I didn't get a chance to build it again with MSVC, so should probably do that before merging.

[jalius]

Wondering if we should change
int osal_thread_create(void *thandle, int stacksize, void *func, void *param)
parameter void *thandle to OSAL_THREAD_HANDLE *thandle
for clarity in all implementations.

[jalius]

MSVC needed a small tweak to headers to make it build happily with Visual Studio 17 2022.

Developer Command Prompt for VS 2022

SOEM\build-msvc> cmake .. -G "Visual Studio 17 2022"
SOEM\build-msvc> msbuild SOEM.sln

cmd.exe

SOEM\build-gnuc> cmake .. -G "MSYS Makefiles"
SOEM\build-gnuc> make

Build succeeds for both and I can run the simple_test.exe successfully on a hardware target:

GNUC Simple Test:

SOEM\build-gnuc\test\linux\simple_test>simple_test.exe \Device\NPF_{0710CB60-EDF7-4356-BE31-2C366A43D984}
SOEM (Simple Open EtherCAT Master)
Simple test
Starting simple test
ec_init on \Device\NPF_{0710CB60-EDF7-4356-BE31-2C366A43D984} succeeded.
1 slaves found and configured.
Slaves mapped, state to SAFE_OP.
segments : 1 : 687 0 0 0
Request operational state for all slaves
Calculated workcounter 3
Operational state reached for all slaves.
Processdata cycle  162, WKC 3 , O: 00 00 00 00 00 00 00 00 I: 30 00 03 00 0^C02 02 00 T:791067700875279400

MSVC Simple Test:

SOEM\build-msvc\test\linux\simple_test>Debug\simple_test.exe \Device\NPF_{0710CB60-EDF7-4356-BE31-2C366A43D984}
SOEM (Simple Open EtherCAT Master)
Simple test
Starting simple test
ec_init on \Device\NPF_{0710CB60-EDF7-4356-BE31-2C366A43D984} succeeded.
1 slaves found and configured.
Slaves mapped, state to SAFE_OP.
segments : 1 : 687 0 0 0
Request operational state for all slaves
Calculated workcounter 3
Operational state reached for all slaves.
^Cocessdata cycle  262, WKC 3 , O: 00 00 00 00 00 00 00 00 I: 30 00 03 00 00 02 02 00 T:791067756981503160

@ArthurKetels Any concerns on merging this to support cross-tool building on windows? The change should not interfere with existing project, I kept it as minimal as possible to get MSYS/GNUC working.

[ArthurKetels]

Thanks for the work and testing. Looks good.