How to start reading gcc source code.

[hgbasm]

Hi there people, I beed watching some options, also reading some things, 
now I know this:

C:\hgb_Progs\MinGW\include>gcc -c -save-temps -no-integrated-cpp 
-aux-info winoutt.txt windows.c
windows.c:16:13: warning: #pragma system_header ignored outside include file


With this are generated the following files:

winoutt.txt => contain the names of a serie of all the functions defined
windows.I => contains typedefs, enums, structs and some lines like:

# 1 "<command line>"
# 1 "windows.c"
# 47 "windows.c"
# 1 "C:/hgb_Progs/MinGW/include/stdarg.h" 1 3



# 1 "C:/hgb_Progs/MinGW/lib/gcc-lib/mingw32/3.2.3/include/stdarg.h" 1 3
# 44 "C:/hgb_Progs/MinGW/lib/gcc-lib/mingw32/3.2.3/include/stdarg.h" 3
typedef __builtin_va_list __gnuc_va_list;


Some one can explain me what they mean?, I guess that handle the depth 
level, but dont know how to read it......




I remember that with a switch I obtain a file with extension "II" 
instead of only "I" or was a espegism?




Now the only other thing that I whant to get are the defines :), is 
there a switch or a way I can get them?, like the file winoutt.txt 
generated with -aux-info


By the way, the other switch are redundant?, and what mean:

windows.c:16:13: warning: #pragma system_header ignored outside include file



If I can get the defines listed in such a beatifull way I will really be 
happy, and start coding a translator with some tool like antrl or some 
like that, pheraphs a hand tool one.



I have downloaded the full packege gcc 4. I have some what understand a 
little about  three.def/.c/.h, the instructions gived in 
http://gcc.gnu.org/install/ are sufficient to compile the entire package 
for win?, or should I ask mingw how they port it? (sorry for that question)

Another question related to the information, is suficient with read 
http://gcc.gnu.org/onlinedocs/ ? or I need to read more about how gcc work?