CMake: better implicit behavior for WITH_WINDOWLESS{EGL,GLX}APPLICATION.

I found a way how to hack cmake_dependent_option() beyond just
specifying a list of things AND-ed togeter -- if one uses spaces instead
of `;`, all the contents are passed to a single if() statement and it's
possible to use parentheses, AND, OR and all other stuff.

Now, WindowlessEglApplication is implicitly enabled if targeting
non-desktop ES and magnum-info utility is enabled, because magnum-info
depends on it in that case. In all other cases it is implicitly disabled
with ability to enable it.

WindowlessGlxApplication is now available only when targeting desktop GL
or desktop GLES and is implicitly enabled when magnum-info or any other
GL utility is enabled.

CMakeLists.txt

@@ -93,8 +93,8 @@ cmake_dependent_option(WITH_AL_INFO "Build magnum-al-info utility" OFF "WITH_AUD
 # EGL context and windowless EGL application, available everywhere except on
 # platforms which don't support extension loading
 if(NOT CORRADE_TARGET_EMSCRIPTEN AND NOT CORRADE_TARGET_NACL)
+    cmake_dependent_option(WITH_WINDOWLESSEGLAPPLICATION "Build WindowlessEglApplication library" OFF "NOT TARGET_GLES OR TARGET_DESKTOP_GLES OR NOT WITH_MAGNUMINFO" ON)
     option(WITH_EGLCONTEXT "Build EglContext library" OFF)
-    option(WITH_WINDOWLESSEGLAPPLICATION "Build WindowlessEglApplication library" OFF)
 endif()
 
 # NaCl-specific application libraries
@@ -118,9 +118,11 @@ elseif(CORRADE_TARGET_APPLE)
 # X11 + GLX/EGL-specific application libraries
 elseif(CORRADE_TARGET_UNIX)
     option(WITH_GLXAPPLICATION "Build GlxApplication library" OFF)
-    cmake_dependent_option(WITH_WINDOWLESSGLXAPPLICATION "Build WindowlessGlxApplication library" OFF "NOT WITH_MAGNUMINFO;NOT WITH_FONTCONVERTER;NOT WITH_DISTANCEFIELDCONVERTER" ON)
+    if(NOT TARGET_GLES OR TARGET_DESKTOP_GLES)
+        cmake_dependent_option(WITH_WINDOWLESSGLXAPPLICATION "Build WindowlessGlxApplication library" OFF "NOT WITH_MAGNUMINFO;NOT WITH_FONTCONVERTER;NOT WITH_DISTANCEFIELDCONVERTER" ON)
+        option(WITH_GLXCONTEXT "Build GlxContext library" OFF)
+    endif()
     option(WITH_XEGLAPPLICATION "Build XEglApplication library" OFF)
-    option(WITH_GLXCONTEXT "Build GlxContext library" OFF)
 
 # Windows-specific application libraries
 elseif(CORRADE_TARGET_WINDOWS)