Libsdl-ttf

Hi,
I’ve downloaded the libsdl-ttf but I can’t compiling the example by

gcc showfont.c sdl-config --cflags --libs -O2 -o go
showfont.c:7:21: SDL_ttf.h: No such file or directory
showfont.c: In function main': showfont.c:19: error:TTF_Font’ undeclared (first use in this function)
showfont.c:19: error: (Each undeclared identifier is reported only once
showfont.c:19: error: for each function it appears in.)
showfont.c:19: error: font' undeclared (first use in this function) showfont.c:40: error:TTF_STYLE_NORMAL’ undeclared (first use in this
function)
showfont.c:53: error: TTF_STYLE_BOLD' undeclared (first use in this function) showfont.c:56: error:TTF_STYLE_ITALIC’ undeclared (first use in this
function)
showfont.c:59: error: TTF_STYLE_UNDERLINE' undeclared (first use in this function) showfont.c:86: error:TTF_Quit’ undeclared (first use in this function)
showfont.c:134: warning: assignment makes pointer from integer without a
cast
showfont.c:136: warning: assignment makes pointer from integer without a
cast
showfont.c:156: warning: assignment makes pointer from integer without a
cast
showfont.c:158: warning: assignment makes pointer from integer without a
cast
showfont.c:164: warning: assignment makes pointer from integer without a
cast
showfont.c:166: warning: assignment makes pointer from integer without a
cast
showfont.c:185: warning: assignment makes pointer from integer without a
cast
showfont.c:188: warning: assignment makes pointer from integer without a
cast

why?
tnx