Trying to figure out why this wont work on Ubuntu 18.10 (Cosmic)

libaom_import_poc.c

#include <stdio.h>
#include <stdlib.h>

#include <aom/aom_decoder.h>
#include <aom/aomdx.h>

// This is a minimal example of trying to import libaom's decoding functionality, as seen in
// ffmpeg/libavformat's source code. First ensure libaom-dev is installed on your machine with
// a version greater than or equal to 1.x
//
//     sudo apt install libaom-dev
//
// Then simply compile:
//
//     gcc -Wall -g libaom_import_poc.c
//
int main()
{
    printf("Hello world!\n");
    return 0;
}

I keep getting

$ gcc -Wall -g libaom_import_poc.c
/usr/bin/ld: /tmp/ccm5X9V7.o: in function `aom_codec_control_AOM_SET_POSTPROC':
/usr/include/aom/aom.h:119: undefined reference to `aom_codec_control_'
/usr/bin/ld: /tmp/ccm5X9V7.o: in function `aom_codec_control_AOM_SET_DBG_COLOR_REF_FRAME':
/usr/include/aom/aom.h:121: undefined reference to `aom_codec_control_'
/usr/bin/ld: /tmp/ccm5X9V7.o: in function `aom_codec_control_AOM_SET_DBG_COLOR_MB_MODES':
/usr/include/aom/aom.h:123: undefined reference to `aom_codec_control_'
/usr/bin/ld: /tmp/ccm5X9V7.o: in function `aom_codec_control_AOM_SET_DBG_COLOR_B_MODES':
/usr/include/aom/aom.h:125: undefined reference to `aom_codec_control_'
/usr/bin/ld: /tmp/ccm5X9V7.o: in function `aom_codec_control_AOM_SET_DBG_DISPLAY_MV':
/usr/include/aom/aom.h:127: undefined reference to `aom_codec_control_'
/usr/bin/ld: /tmp/ccm5X9V7.o:/usr/include/aom/aom.h:129: more undefined references to `aom_codec_control_' follow
collect2: error: ld returned 1 exit status