CMake: Make all cache options appear even in case of errors

The `option` commands have been moved to the top of the file, so that
the relevant options are registered in the CMake cache even if one of
the required libraries is not found. This solves an ergonomic problem
when using bundled libraries where you have to first download GLFW
before being able to select the option to also download Qt.

CMakeLists.txt

@@ -35,6 +35,13 @@ endfunction()
 
 project(citra)
 
+option(ENABLE_GLFW "Enable the GLFW frontend" ON)
+option(CITRA_USE_BUNDLED_GLFW "Download bundled GLFW binaries" OFF)
+
+option(ENABLE_QT "Enable the Qt frontend" ON)
+option(CITRA_USE_BUNDLED_QT "Download bundled Qt binaries" OFF)
+option(CITRA_FORCE_QT4 "Use Qt4 even if Qt5 is available." OFF)
+
 if(NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/.git/hooks/pre-commit)
     message(STATUS "Copying pre-commit hook")
     file(COPY hooks/pre-commit
@@ -129,8 +136,6 @@ list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/externals/cmake-modules")
 find_package(OpenGL REQUIRED)
 include_directories(${OPENGL_INCLUDE_DIR})
 
-option(ENABLE_GLFW "Enable the GLFW frontend" ON)
-option(CITRA_USE_BUNDLED_GLFW "Download bundled GLFW binaries" OFF)
 if (ENABLE_GLFW)
     if (CITRA_USE_BUNDLED_GLFW)
         # Detect toolchain and platform
@@ -176,9 +181,6 @@ ELSE()
     set(PLATFORM_LIBRARIES rt)
 ENDIF (APPLE)
 
-option(ENABLE_QT "Enable the Qt frontend" ON)
-option(CITRA_USE_BUNDLED_QT "Download bundled Qt binaries" OFF)
-option(CITRA_FORCE_QT4 "Use Qt4 even if Qt5 is available." OFF)
 if (ENABLE_QT)
     if (CITRA_USE_BUNDLED_QT)
         if (MSVC14 AND ARCHITECTURE_x86_64)