GCC's manual or POSIX say about the '-D' option something like: '−D name[=value]' should be treated as if in directive '#define name value' (with '1' as default for the value), including its tokenization. So an option like '-DM(X, Y)=...' should be processed like a directive '#define M(X, Y) ...'. However, the current code treat a space as a separator between the macro and its definition, just like the '='. As consequence, the above option is processed like the directive would be '#define M(X, Y)=...', with 'M(X,' as the macro (name) and 'Y)=...' as its definition. Fix this by stopping to treat the space character specially, thus only using '=' as the separator. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>