ref: ed1a8159a3f06e7c4da43567e8dee276d392f3bd
dir: /tests/cc/execute/0119-macrostr.c/
#define B "b" char s[] = "a" B "c"; int main() { if (s[0] != 'a') return 1; if (s[1] != 'b') return 2; if (s[2] != 'c') return 3; if (s[3] != '\0') return 4; return 0; }