Improve stack-trace for ecode symbols.

Fix demangling in stack-trace for mingw builds.
Fix all stat calls in windows mingw builds that fail to detect files / dirs when the path ends with a path separator (this is an old bug, as old as I can remember, I thought it was fixed on mingw side but it seems only works for the cross compiled build, windows mingw build was failing catastrophically and never saw it).
There was also a very old minor bug in Sys::getProcessPath.

premake4.lua

@@ -1738,6 +1738,7 @@ solution "eepp"
 				linkoptions { "../../bin/assets/icon/ecode.res" }
 			end
 			buildoptions{ "-Wa,-mbig-obj" }
+			linkoptions { "-Wl,--export-all-symbols" }
 		end
 		build_link_configuration( "ecode", false )
 		configuration { "release", "windows" }