Take file$\_$exists$()$ out of main.c$,$ and put it into a file called my$\_$which$\_$lib.c $2.$ Create a header file called my$\_$which. h$,$ and write a function signature for inside. It's just $1$ line of code. $3.$ Make sure you include my$\_$which.h inside of $4.$ Move all source files $($main$.$c$,$ my$\_$which.h$,$ and my$\_$which$\_$lib.c$)$ into a folder called $5.$ Create a makefile called $-$ static: compiles into a static library called $.$ Move any intermediate objects into don't exist. into a shared library called libmy$\_$which. so$.$ Move this file into a subdirectory called $.$ Move any intermediate objects into This directive should make those directories if they don't exist. $-$ all: compiles main.c into the executable. It should statically link to Move the finished executable into $.$ Move any intermediate objects into This directive should make those directories if they don't exist. $-$ clean: removes all build artifacts including the build directories.