Why is gcc failing with 'unrecognized command line option "-L/lusr/opt/mpfr-2.4.2/lib"'?

My sysadmin recently installed a new version of GCC, in /lusr/opt/gcc-4.4.3. I tested it as follows:

mike@canon:~$ cat test.cint main(){  return 0;}mike@canon:~$ gcc test.c/lusr/opt/gcc-4.4.3/libexec/gcc/i686-pc-linux-gnu/4.4.3/cc1: error while loading shared libraries: libmpfr.so.1: cannot open shared object file: No such file or directory

After informing my sysadmin about this, he said to add /lusr/opt/mpfr-2.4.2/lib:/lusr/opt/gmp-4.3.2/lib to my LD_LIBRARY_PATH. After doing this, I get the following error:

mike@canon:~$ gcc test.ccc1: error: unrecognized command line option "-L/lusr/opt/mpfr-2.4.2/lib"

First, my sysadmin wasn't entirely sure this was the best workaround(though he did say it worked for him...), so is there a better solution?

Second, why am I getting a linker error from cc, and how can I fix it?

Some information which may be helpful:

mike@canon:~$ env | grep mpfrOLDPWD=/lusr/opt/mpfr-2.4.2/libLD_LIBRARY_PATH=/lusr/opt/mpfr-2.4.2/lib:/lusr/opt/gmp-4.3.2/lib:mike@canon:~$ echo $LDFLAGS(the above is a blank line)