a few beginner questiosn

[BLUE 3TOO]

Hi,
 
    I have following questions and would appreciate any comment. Thanks you very much.
 
    1. How to build a debugable version of GCC? I tried to set CFLGAS & CXXFLAGS to "-O0 -g -fno-inline" in my configure command line, but it seems it doesn't work. I manually modify all the Makefiles in gcc sub-directories and replace "-O2" with "-O0 -g", it is dumb but works. I guess there is a better way that I am not aware of. Can anybody tell me how to do it? 
 
    2. during the "make" process, i noticed it enters  gcc-4.5.0/host-i686-pc-cygwin/gcc and build the same source files three times:
 
       E.g. first time:   gcc .././gcc/c-typeck.c -o c-typeck.o
             2nd time:   xgcc -O2 -gtoggle .././gcc/c-typeck.c -o c-typeck.o
             3rd time:    xgcc -O2 -DIN_GCC .././gcc/c-typeck.c -o c-typeck.o
        Can anybody tells me what these compilation for? Seems that the first one is building gcc, how about 2nd and 3rd one? thanks
 
     3. what is libgcc and newlib for? 
 
     4. what are these directories for?
            prev-i686-pc-cygwin/
            stage1-i686-pc-cygwin/
 
 
      5. what is libssp for? what is lto-plugin for?
 
 
     thank you very much.
  		 	   		  
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