CMake has a list DATA type. A list is stored as a STRING of semicolon-separated list elements. Whitespace separated arguments to a SET statement are interpreted as list elements. For INSTANCE, SET(var a b c d e) will give "var" a value of a;b;c;d;e and this list can be used by other CMake commands. However, if you pass ${var} to a non-CMake external tool, such as a compiler's command line, you are passinga;b;c;d;e which is not what you want. Instead you either NEED to pass "${var}", so that the list will be converted to a whitespace-separated string, or you need to SET(var "a b c d e") in the 1st place so that you're working with a string, not a list.

CMake has a list data type. A list is stored as a string of semicolon-separated list elements. Whitespace separated arguments to a SET statement are interpreted as list elements. For instance, SET(var a b c d e) will give "var" a value of a;b;c;d;e and this list can be used by other CMake commands. However, if you pass ${var} to a non-CMake external tool, such as a compiler's command line, you are passinga;b;c;d;e which is not what you want. Instead you either need to pass "${var}", so that the list will be converted to a whitespace-separated string, or you need to SET(var "a b c d e") in the 1st place so that you're working with a string, not a list.