apple: Fix some warnings
apple: Fix stringWithFormat warnings
apple: Enable extra compiler warnings for OSX.
Merge pull request #1150 from lioncash/osx

Fix some warnings on OSX.
Merge pull request #1151 from lioncash/cwarn

apple: Enable extra compiler warnings for OSX.
Merge pull request #1149 from crazyquark/master

Xcode 6.0.1 fixes
(Shaders) Fix 'declaration shadows a variable in local scope' warnings
(fonts.c) Fix 'declaration shadows a global variable' warning
(gl_common.c) Fix declaration shadows a variable in global scope warning
input_autodetect.c - Fix 'declaration shadows a global variable' warning
input_common.c - Get rid of variable shadowing warnings
message_queue.c - Fix warnings
driver.c - Fix warnings 'declaration shadows a global variable'
retroarch.c - Fix 'declaration shadows a local variable'
(menu_shader.c) Fix 'declaration(s) shadows variables in local/global scope' warnings
(menu_action.c) Fix 'declaration shadows a global variable' warning
resampler.c - Fix 'delcaration shadows a variable in global scope'
settings_data.c - Make all of the 'append list' leaf functions static functions
(menu_shader.c) Build fix
Get rid of some 'no previous prototype for function' warnings in lakka.c and rgui.c