gcc -D

gcc -D 옵션 (Dmacro) http://www.network-theory.co.uk/docs/gccintro/gccintro_35.html

-DTEST
<=>  코드내 #define TEST
<=>  코드내 #define TEST 1

-DTEST=5
<=> -DTEST="5"
<=> 코드내 #define TEST 5

-DTEST='"test"'
<=>코드내 #define TEST "test"

-D'test(x)=xtest(x)'
<=>코드내 #define test(x) xtext(x)