Fix examples compilation

Makefile

@@ -12,7 +12,10 @@ OBJ = \
 	src/main.o 
 
 EXAMPLES = \
-	example/basic.o
+	example/basic \
+	example/riemman \
+	example/n-cube \
+	example/lens
 
 CFLAGS = \
 	-I./ext/cglm/include  \
@@ -39,6 +42,8 @@ help:
 	@echo "	$(MAKE) linux-wayland"
 	@echo "	$(MAKE) cocoa"
 	@echo "	$(MAKE) CC=emcc wasm"
+	@echo "Examples"
+	@echo "	$(MAKE) examples"
 	@echo "Clean"
 	@echo "	$(MAKE) clean"
 
@@ -72,7 +77,7 @@ libglfw.so:
 	$(CC) -fPIC -shared $(DFLAGS) -D_GLFW_BUILD_DLL -Iext/glfw/deps/wayland ./ext/glfw/src/*.c -o $@ 
 
 clean:
-	rm $(OBJ) $(BIN) 
+	rm $(OBJ) $(BIN) $(EXAMPLES)
 	cd ext; $(MAKE) -f glfw.mk clean; cd -
 
 
@@ -82,3 +87,7 @@ examples: $(EXAMPLES)
 
 .c.o:
 	$(CC) -Wno-implicit-function-declaration $(CFLAGS) -c -o $@ $<
+
+.c:
+	$(CC) -lm -Wno-implicit-function-declaration $(CFLAGS) -c -o $@ $<
+