Logging: Add customizable logging backends and fmtlib based macros

* Change the logging backend to support multiple sinks through the
Backend Interface
* Add a new set of logging macros to use fmtlib instead.
* Qt: Compile as GUI application on windows to make the console hidden by
default. Add filter configuration and a button to open log location.
* SDL: Migrate to the new logging macros

src/citra_qt/CMakeLists.txt

@@ -28,6 +28,8 @@ add_executable(citra-qt
     configuration/configure_system.h
     configuration/configure_web.cpp
     configuration/configure_web.h
+    debugger/console.h
+    debugger/console.cpp
     debugger/graphics/graphics.cpp
     debugger/graphics/graphics.h
     debugger/graphics/graphics_breakpoint_observer.cpp
@@ -165,6 +167,14 @@ if (APPLE)
     target_sources(citra-qt PRIVATE ${MACOSX_ICON})
     set_target_properties(citra-qt PROPERTIES MACOSX_BUNDLE TRUE)
     set_target_properties(citra-qt PROPERTIES MACOSX_BUNDLE_INFO_PLIST ${CMAKE_CURRENT_SOURCE_DIR}/Info.plist)
+elseif(WIN32)
+    # compile as a win32 gui application instead of a console application
+    target_link_libraries(citra-qt PRIVATE Qt5::WinMain)
+    if(MSVC)
+        set_target_properties(citra-qt PROPERTIES LINK_FLAGS_RELEASE "/SUBSYSTEM:WINDOWS")
+    elseif(MINGW)
+        set_target_properties(citra-qt PROPERTIES LINK_FLAGS_RELEASE "-mwindows")
+    endif()
 endif()
 
 create_target_directory_groups(citra-qt)