Improve Windows compatibility and function exports

Comment out static linking options in CMakeLists.txt.
Add Windows-specific includes and DllMain definition in DllMain.cpp.
Define DLLEXPORT macro in exportedfunctions.cpp for cross-compiler compatibility.

libmexlibczi/CMakeLists.txt

@@ -17,6 +17,6 @@ if(WIN32)
  #set_target_properties(MatlabCZI PROPERTIES SUFFIX ".mexw64")
 elseif(UNIX)
  #set_target_properties(MatlabCZI PROPERTIES SUFFIX ".mexa64")
- target_link_options(libmexlibczi PRIVATE -static-libgcc -static-libstdc++ )
+ #target_link_options(libmexlibczi PRIVATE -static-libgcc -static-libstdc++ )
  set_target_properties(MatlabCZI PROPERTIES PREFIX "") # otherwise "lib" is prepended
 endif()

libmexlibczi/DllMain.cpp

@@ -1,3 +1,4 @@
+#if _WIN32
 #include <Windows.h>
 
 BOOL APIENTRY DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved)
@@ -23,3 +24,4 @@ BOOL APIENTRY DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserv
 
     return TRUE;
 }
+#endif

libmexlibczi/exportedfunctions.cpp

@@ -1,16 +1,22 @@
 #include <include/function.h>
 
-extern "C" __declspec(dllexport) void mexFunction(int nlhs, Parameter plhs[], int nrhs, const Parameter prhs[], IAppExtensionFunctions* app_functions)
+#ifdef __GNUC__
+#define DLLEXPORT __attribute__((visibility("default")))
+#else
+#define DLLEXPORT __declspec(dllexport)
+#endif
+
+extern "C" DLLEXPORT void mexFunction(int nlhs, Parameter plhs[], int nrhs, const Parameter prhs[], IAppExtensionFunctions* app_functions)
 {
     mexlibCZI::mexFunction(nlhs, plhs, nrhs, prhs, app_functions);
 }
 
-extern "C" __declspec(dllexport) void OnInitialize()
+extern "C" DLLEXPORT void OnInitialize()
 {
     mexlibCZI::OnInitialize();
 }
 
-extern "C" __declspec(dllexport) void OnShutdown()
+extern "C" DLLEXPORT void OnShutdown()
 {
     mexlibCZI::OnShutdown();
 }