changing gcc's include paths?

[christopher j bottaro <cjb cs utexas edu>]

hello,
i'm trying to compile MPlayer with libmp3lame support.  lame is installed in 
/shared.  thus the include files for lame are in /shared/include/lame.  here 
is part of the configure.log that shows were autodetection of lame failed:

#include <lame/lame.h>
int main(void) { lame_version_t lv; (void) lame_init(); 
get_lame_version_numerical(&lv);  printf("%d%d\n",lv.major,lv.minor); return 
0; }

gcc    /tmp/mplayer-conf-455-24277.c -o /tmp/mplayer-conf-7441-24277.o 
-lmp3lame -lvorbis -logg -lm
/tmp/mplayer-conf-455-24277.c:1:23: lame/lame.h: No such file or directory
/tmp/mplayer-conf-455-24277.c: In function `main':
/tmp/mplayer-conf-455-24277.c:2: `lame_version_t' undeclared (first use in 
this function)
/tmp/mplayer-conf-455-24277.c:2: (Each undeclared identifier is reported only 
once
/tmp/mplayer-conf-455-24277.c:2: for each function it appears in.)
/tmp/mplayer-conf-455-24277.c:2: parse error before "lv"
/tmp/mplayer-conf-455-24277.c:2: `lv' undeclared (first use in this function)

ok, i don't know anything about configure scripts, but i do know that is some 
c code that is trying to include lame/lame.h.  my question is how can i make 
gcc look for headers in /shared/include (along with all the defaults like 
/usr/include, /usr/local/include, etc)?

thanks for the help,
christopher