Update example makefiles to check the new homebrew paths (#4003)

Homebrew on Apple Silicon (i.e. Macbook Air/Pro M1) use `/opt/homebrew` instead of /usr/local.

examples/example_glfw_metal/Makefile

@@ -14,9 +14,10 @@ SOURCES += $(IMGUI_DIR)/backends/imgui_impl_glfw.cpp $(IMGUI_DIR)/backends/imgui
 OBJS = $(addsuffix .o, $(basename $(notdir $(SOURCES))))
 
 LIBS = -framework Metal -framework MetalKit -framework Cocoa -framework IOKit -framework CoreVideo -framework QuartzCore
-LIBS += -L/usr/local/lib -lglfw
+LIBS += -L/usr/local/lib -L/opt/homebrew/lib
+LIBS += -lglfw
 
-CXXFLAGS = -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends -I/usr/local/include
+CXXFLAGS = -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends -I/usr/local/include -I/opt/homebrew/include
 CXXFLAGS += -Wall -Wformat
 CFLAGS = $(CXXFLAGS)
 

examples/example_glfw_opengl2/Makefile

@@ -41,11 +41,11 @@ endif
 ifeq ($(UNAME_S), Darwin) #APPLE
 	ECHO_MESSAGE = "Mac OS X"
 	LIBS += -framework OpenGL -framework Cocoa -framework IOKit -framework CoreVideo
-	LIBS += -L/usr/local/lib -L/opt/local/lib
+	LIBS += -L/usr/local/lib -L/opt/local/lib -L/opt/homebrew/lib
 	#LIBS += -lglfw3
 	LIBS += -lglfw
 
-	CXXFLAGS += -I/usr/local/include -I/opt/local/include
+	CXXFLAGS += -I/usr/local/include -I/opt/local/include -I/opt/homebrew/include
 	CFLAGS = $(CXXFLAGS)
 endif
 

examples/example_glfw_opengl3/Makefile

@@ -80,11 +80,11 @@ endif
 ifeq ($(UNAME_S), Darwin) #APPLE
 	ECHO_MESSAGE = "Mac OS X"
 	LIBS += -framework OpenGL -framework Cocoa -framework IOKit -framework CoreVideo
-	LIBS += -L/usr/local/lib -L/opt/local/lib
+	LIBS += -L/usr/local/lib -L/opt/local/lib -L/opt/homebrew/lib
 	#LIBS += -lglfw3
 	LIBS += -lglfw
 
-	CXXFLAGS += -I/usr/local/include -I/opt/local/include
+	CXXFLAGS += -I/usr/local/include -I/opt/local/include -I/opt/homebrew/include
 	CFLAGS = $(CXXFLAGS)
 endif