GCC's search paths

[Gerwyn Davies]

I'm reasonably new to the GNU tools, and I was 
very surprised when I typed 'gcc -print-search-dirs' and got a 10 line long 
search path for both the programs and the libraries!
 
What determines gcc's search paths?
 
I've set LIBRARY_PATH in the environment, but that made no 
difference.
 
Many thanks.
 
 
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