Update CMakeLists

Define library.

CMakeLists.txt

@@ -5,6 +5,12 @@ set(CMAKE_C_STANDARD 11)
 
 include_directories(.)
 
+add_library(
+midi_utils STATIC
+midi-utils.c
+midi-utils.h
+)
+
 add_executable(
   test-note-names
     test-note-names.c
@@ -18,3 +24,4 @@ add_custom_command(
     "${CMAKE_HOME_DIRECTORY}/cases.txt"
     $<TARGET_FILE_DIR:test-note-names>
 )
+