Fix cmake warnings when using BUILD_STATIC and AUTOGEN for Qt

"Warning: Policy CMP0071 is not set: Let AUTOMOC and AUTOUIC process GENERATED files. ..."

Magnum allows really old cmake versions (3.4), so we check the version to ensure the SKIP_AUTOGEN property exists.

Also fix a spelling mistake in WITH_PRIMITIVES option.

CMakeLists.txt

@@ -105,7 +105,7 @@ cmake_dependent_option(WITH_TEXT "Build Text library" ON "NOT WITH_FONTCONVERTER
 cmake_dependent_option(WITH_TEXTURETOOLS "Build TextureTools library" ON "NOT WITH_TEXT;NOT WITH_DISTANCEFIELDCONVERTER" ON)
 cmake_dependent_option(WITH_TRADE "Build Trade library" ON "NOT WITH_MESHTOOLS;NOT WITH_PRIMITIVES;NOT WITH_IMAGECONVERTER;NOT WITH_ANYIMAGEIMPORTER;NOT WITH_ANYIMAGECONVERTER;NOT WITH_ANYSCENEIMPORTER;NOT WITH_OBJIMPORTER;NOT WITH_TGAIMAGECONVERTER;NOT WITH_TGAIMPORTER" ON)
 cmake_dependent_option(WITH_GL "Build GL library" ON "NOT WITH_SHADERS;NOT WITH_GL_INFO;NOT WITH_ANDROIDAPPLICATION;NOT WITH_WINDOWLESSIOSAPPLICATION;NOT WITH_CGLCONTEXT;NOT WITH_GLXAPPLICATION;NOT WITH_GLXCONTEXT;NOT WITH_XEGLAPPLICATION;NOT WITH_WINDOWLESSWGLAPPLICATION;NOT WITH_WGLCONTEXT;NOT WITH_WINDOWLESSWINDOWSEGLAPPLICATION;NOT WITH_DISTANCEFIELDCONVERTER" ON)
-option(WITH_PRIMITIVES "Builf Primitives library" ON)
+option(WITH_PRIMITIVES "Build Primitives library" ON)
 
 cmake_dependent_option(TARGET_HEADLESS "Build command-line utilities for use on a headless machines" OFF "WITH_GL" OFF)
 cmake_dependent_option(TARGET_GL "Build libraries with OpenGL interoperability" ON "WITH_GL" OFF)

src/Magnum/Shaders/CMakeLists.txt

@@ -69,6 +69,10 @@ if(BUILD_STATIC)
     set_property(SOURCE ${MagnumShaders_RCS} APPEND PROPERTY COMPILE_DEFINITIONS
         "CORRADE_AUTOMATIC_INITIALIZER=CORRADE_NOOP"
         "CORRADE_AUTOMATIC_FINALIZER=CORRADE_NOOP")
+    # Avoid warning when using AUTOGEN for Qt
+    if(NOT (${CMAKE_VERSION} VERSION_LESS "3.8.0"))
+        set_property(SOURCE ${MagnumShaders_RCS} PROPERTY SKIP_AUTOGEN ON)
+    endif()
 endif()
 target_include_directories(MagnumShadersObjects PUBLIC
     $<TARGET_PROPERTY:Magnum,INTERFACE_INCLUDE_DIRECTORIES>

src/Magnum/TextureTools/CMakeLists.txt

@@ -41,6 +41,10 @@ if(TARGET_GL)
             COMPILE_DEFINITIONS
                 "CORRADE_AUTOMATIC_INITIALIZER=CORRADE_NOOP"
                 "CORRADE_AUTOMATIC_FINALIZER=CORRADE_NOOP")
+        # Avoid warning when using AUTOGEN for Qt
+        if(NOT (${CMAKE_VERSION} VERSION_LESS "3.8.0"))
+            set_property(SOURCE ${MagnumTextureTools_RCS} PROPERTY SKIP_AUTOGEN ON)
+        endif()
     endif()
 
     list(APPEND MagnumTextureTools_SRCS