Fixed building on Linux GCC

Author: GermanAizek

CMakeLists.txt

@@ -10,6 +10,10 @@ else()
     add_executable(midi2mod main.c midi.h midi.c stringcatalog.h stringcatalog.c mod.h mod.c)
 endif()
 
+if(UNIX)
+    set(CMAKE_C_FLAGS "-lm")
+endif()
+
 if(WIN32)
     target_link_libraries(midi2mod wsock32 ws2_32)
 endif()