It should be PREFIX, not INSTALL_PATH

Makefile

@@ -14,7 +14,7 @@ clean:
 	$(RM) yaitaa obj/*
 
 install:
-	install -D -m 755 yaitaa $(INSTALL_PATH)/yaitaa
+	install -D -m 755 yaitaa $(PREFIX)/bin/yaitaa
 
 yaitaa: lib
 	$(CC) $(CFLAGS) src/main.c $(INCLUDES) $(OBJECTS) $(CLIBS) -o ./yaitaa

README.md

@@ -66,14 +66,14 @@ strip ./yaitaa
 
 ```sh
 # as root
-make install
+make install # Will install it to /bin/
 ```
 
 Alternatively, you can install it to your local user directory, if it's in your
 `$PATH`:
 
 ```sh
-make install INSTALL_PATH=$HOME/.local/bin
+make install PREFIX=$HOME/.local/ # will install it to $HOME/.local/bin/
 ```
 
 ## License