Examples: Fix 'How to build' instructions for SDL2 examples (#2012)

examples/example_sdl_opengl2/README.md

@@ -5,18 +5,18 @@
 
 ```
 set SDL2DIR=path_to_your_sdl2_folder
-cl /Zi /MD /I %SDL2DIR%\include /I ..\.. main.cpp ..\imgui_impl_sdl.cpp ..\imgui_impl_opengl2.cpp ..\..\imgui*.cpp /link /LIBPATH:%SDL2DIR%\lib SDL2.lib SDL2main.lib opengl32.lib /subsystem:console
+cl /Zi /MD /I %SDL2DIR%\include /I .. /I ..\.. main.cpp ..\imgui_impl_sdl.cpp ..\imgui_impl_opengl2.cpp ..\..\imgui*.cpp /link /LIBPATH:%SDL2DIR%\lib SDL2.lib SDL2main.lib opengl32.lib /subsystem:console
 ```
 
 - On Linux and similar Unixes
 
 ```
-c++ `sdl2-config --cflags` -I ../.. main.cpp ../imgui_impl_sdl.cpp ../imgui_impl_opengl2.cpp ../../imgui*.cpp `sdl2-config --libs` -lGL
+c++ `sdl2-config --cflags` -I .. -I ../.. main.cpp ../imgui_impl_sdl.cpp ../imgui_impl_opengl2.cpp ../../imgui*.cpp `sdl2-config --libs` -lGL
 ```
 
 - On Mac OS X
 
 ```
 brew install sdl2
-c++ `sdl2-config --cflags` -I ../.. main.cpp ../imgui_impl_sdl.cpp ../imgui_impl_opengl2.cpp ../../imgui*.cpp `sdl2-config --libs` -framework OpenGl
+c++ `sdl2-config --cflags` -I .. -I ../.. main.cpp ../imgui_impl_sdl.cpp ../imgui_impl_opengl2.cpp ../../imgui*.cpp `sdl2-config --libs` -framework OpenGl
 ```

examples/example_sdl_opengl3/README.md

@@ -5,18 +5,18 @@
 
 ```
 set SDL2DIR=path_to_your_sdl2_folder
-cl /Zi /MD /I ..\.. /I ..\libs\gl3w /I %SDL2DIR%\include main.cpp ..\imgui_impl_sdl.cpp ..\imgui_impl_opengl3.cpp ..\..\imgui*.cpp ..\libs\gl3w\GL\gl3w.c /link /libpath:%SDL2DIR%\lib\x86 SDL2.lib SDL2main.lib opengl32.lib /subsystem:console
+cl /Zi /MD /I .. /I ..\.. /I ..\libs\gl3w /I %SDL2DIR%\include main.cpp ..\imgui_impl_sdl.cpp ..\imgui_impl_opengl3.cpp ..\..\imgui*.cpp ..\libs\gl3w\GL\gl3w.c /link /libpath:%SDL2DIR%\lib\x86 SDL2.lib SDL2main.lib opengl32.lib /subsystem:console
 ```
 
 - On Linux and similar Unixes
 
 ```
-c++ `sdl2-config --cflags` -I ../.. -I ../libs/gl3w main.cpp ../imgui_impl_sdl.cpp ../imgui_impl_opengl3.cpp ../../imgui*.cpp ../libs/gl3w/GL/gl3w.c `sdl2-config --libs` -lGL -ldl
+c++ `sdl2-config --cflags` -I .. -I ../.. -I ../libs/gl3w main.cpp ../imgui_impl_sdl.cpp ../imgui_impl_opengl3.cpp ../../imgui*.cpp ../libs/gl3w/GL/gl3w.c `sdl2-config --libs` -lGL -ldl
 ```
 
 - On Mac OS X
 
 ```
 brew install sdl2
-c++ `sdl2-config --cflags` -I ../.. -I ../libs/gl3w main.cpp ../imgui_impl_sdl.cpp ../imgui_impl_opengl3.cpp ../../imgui*.cpp ../libs/gl3w/GL/gl3w.c `sdl2-config --libs` -framework OpenGl -framework CoreFoundation
+c++ `sdl2-config --cflags` -I .. -I ../.. -I ../libs/gl3w main.cpp ../imgui_impl_sdl.cpp ../imgui_impl_opengl3.cpp ../../imgui*.cpp ../libs/gl3w/GL/gl3w.c `sdl2-config --libs` -framework OpenGl -framework CoreFoundation
 ```