ld & ld.so.conf

["Egor Tur" <worldeb@ukr.net>]

Hi folk.
When I compile programs:
$ g77 -o file -O file.f -lX11
I see:
$ /usr/bin/ld: cannot find -lX11
$ collect2: ld returned 1 exit status
But 
$ cat /etc/ld/so.conf:
$ /usr/X11R6/lib
When I do:
$ g77 -o file -O file.f -L/usr/X11R6/lib -lX11
this OK.
I try:
$export LD_LIBRARY_PATH=/usr/X11R6/lib
$ g77 -o file -O file.f -lX11
$ /usr/bin/ld: cannot find -lX11
$ collect2: ld returned 1 exit status
When I add in /etc/ld.so.conf path to my libraries and compile
program with this libraries - OK, compilation correct.
Why system do not find libX11 library?
I have Debian testing, kernel 2.4.19
Thanx.