You know you could have found where -arch ppc was coming from pretty easily with a blind grep. Then look at the output for likely candidates. It's not like I memorise where everything comes from either. You'll have to learn to look after yourself sooner or later.
I understand your point of view but the purpose of my posts is to give an hand to the MAME team in debugging the OSX ports trying to build binaries on my still-not-so-bad MDD G4, I know that most of answers to my questions are obvious to a developer but what I want is not to learn the whole C programming language but simply to know the few things needed to experiment a little.
Also I am a CMM programmer on my own so while I do not understand everything in the MAME source I can see the logic behind the expressions so I can discover errors but I don't know how to correct them :-D
For example I discovered that most of the error I am encountering declaring the use of GCC and C++ 4.2.1 are because the wrong arguments are passed to the compiler, seems that the gcc versioning of Genie is not working well and some argumetns specific to clang are for example passed to the gcc.
I am currently investigating when this happen...