ref: 0850c5b8bb1562625f822fe7b4e7c0da5f5b28f7 dir: /cmd/cpp/ncat.test/
#define NCAT(a) foo ## a NCAT(bar) #define XCAT(a) ## a foo XCAT(bar) #define CAT3(foo) a##foo##b CAT3(blah)