Hi, I'm trying to compile some code to run it through a debugger it to help myself understand how a certain program works.
The program converts an image format (".anm" extention) into (one or more) Portable Network Graphics format. Later, I'm going to make a program that's capable of converting the reverse, but for now I need to get the proper libraries, which I'm having a bit of a problem with.

This is the source code.
#include <stdio.h>
#include <stdlib.h>
#include <png.h>

typedef signed __int8 int8_t;
typedef unsigned __int8 uint8_t;
typedef signed __int16 int16_t;
typedef unsigned __int16 uint16_t;
typedef signed __int32 int32_t;
typedef unsigned __int32 uint32_t;

typedef struct {
uint32_t regnum;
uint32_t attrnum;
uint32_t resd08;
uint32_t width;
uint32_t height;
uint32_t resd14;
uint32_t resd18;
uint32_t nameofs;
uint32_t resd20;
uint32_t resd24;
uint32_t version;
uint32_t resd2c;
uint32_t entofs;
uint32_t resd34;
uint32_t nextofs;
uint32_t resd3c;
} ANM_ENTRY_HEADER;

typedef struct {
uint32_t version;
uint16_t regnum;
uint16_t attrnum;
uint16_t resw08;
uint16_t width;
uint16_t height;
uint16_t resw0e;
uint32_t nameofs;
uint32_t resd14;
uint32_t resd18;
uint32_t entofs;
uint32_t resd20;
uint32_t nextofs;
uint8_t resx28[24];
} ANM_ENTRY_HEADER_TH11;

typedef struct {
uint32_t magic;
uint16_t resd04;
uint16_t type;
uint16_t width;
uint16_t height;
uint32_t size;
} ANM_THTX_HEADER;

typedef struct {
uint32_t id;
float left;
float top;
float right;
float bottom;
} ANM_REGION;

typedef struct {
uint16_t type;
uint16_t length;
} ANM_ATTRIBUTE_HEADER;

typedef struct {
uint16_t type;
uint16_t length;
uint32_t resd04;
} ANM_ATTRIBUTE_0001;

typedef struct {
uint16_t type;
uint16_t length;
uint32_t resd04;
uint32_t resd08;
} ANM_ATTRIBUTE_0003;

typedef struct {
uint16_t type;
uint16_t length;
uint32_t resd04;
uint32_t resd08;
uint32_t resd0C;
} ANM_ATTRIBUTE_0004;

typedef struct {
uint16_t type;
uint16_t length;
uint32_t resd04;
float resf08;
float resf0C;
float resf10;
} ANM_ATTRIBUTE_000D;

typedef struct {
uint16_t type;
uint16_t length;
uint32_t resd04;
uint32_t resd08;
uint32_t resd0C;
uint32_t resd10;
} ANM_ATTRIBUTE_0022;

typedef struct {
uint16_t type;
uint16_t length;
uint32_t resd04;
uint32_t resd08;
uint32_t resd0C;
float resf10;
float resf14;
} ANM_ATTRIBUTE_0024;

typedef struct {
uint16_t type;
uint16_t length;
uint16_t resw04;
uint16_t resw06;
uint32_t resd08;
} ANM_ATTRIBUTE_004F;

int thtx_to_png(ANM_THTX_HEADER *head, png_byte *bmp, char *outname)
{
char basename[_MAX_FNAME];
char ext[_MAX_EXT];
char newoutname[_MAX_PATH];
char *poutname;
FILE *fp;
png_structp png_ptr;
png_infop info_ptr;
png_byte **image;
png_byte *row;
int i, j;

poutname = outname;
fp = fopen(poutname, "r");
if(fp != NULL) {
fclose(fp);
_splitpath(poutname, NULL, NULL, basename, ext);
for(i = 0; i < INT_MAX; ++i) {
sprintf(newoutname, "%s_%d%s", basename, i, ext);
fp = fopen(newoutname, "r");
if(fp == NULL) break;
fclose(fp);
}
if(i == INT_MAX) return 1;
poutname = newoutname;
}

fp = fopen(poutname, "wb");
if(fp == NULL) {
perror("fopen");
return 1;
}
png_ptr = png_create_write_struct(
PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
info_ptr = png_create_info_struct(png_ptr);
png_init_io(png_ptr, fp);

switch(head->type) {
case 1:
png_set_IHDR(png_ptr, info_ptr, head->width, head->height,
8, PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
png_set_bgr(png_ptr);
png_write_info(png_ptr, info_ptr);

image = malloc(sizeof(png_bytep) * head->height);
for(i = 0; i < head->height; ++i)
image = bmp + i * head->width * 4;
png_write_image(png_ptr, image);
free(image);
break;
case 3:
png_set_IHDR(png_ptr, info_ptr, head->width, head->height,
8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
png_write_info(png_ptr, info_ptr);
row = malloc(sizeof(png_bytep) * head->width * 3);
for(i = 0; i < head->height; ++i) {
for(j = 0; j < head->width; ++j) {
char *p = bmp + (i * head->width + j) * 2;
row[j * 3 + 0] = p[1] & 0xF8;
row[j * 3 + 1] = (p[1] << 5) | ((p[0] & 0xe0) >> 3);
row[j * 3 + 2] = p[0] << 3;
}
png_write_row(png_ptr, row);
}
free(row);
break;
case 5:
png_set_IHDR(png_ptr, info_ptr, head->width, head->height,
8, PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
png_write_info(png_ptr, info_ptr);
row = malloc(sizeof(png_bytep) * head->width * 4);
for(i = 0; i < head->height; ++i) {
for(j = 0; j < head->width; ++j) {
char *p = bmp + (i * head->width + j) * 2;
row[j * 4 + 0] = p[1] << 4;
row[j * 4 + 1] = p[0] & 0xF0;
row[j * 4 + 2] = p[0] << 4;
row[j * 4 + 3] = p[1] & 0xF0;
}
png_write_row(png_ptr, row);
}
free(row);
break;
}

png_write_end(png_ptr, info_ptr);
png_destroy_write_struct(&png_ptr, &info_ptr);
fclose(fp);
printf("succeeded.\n");
return 0;
}

int read_region_info(FILE *fp, uint32_t baseofs, uint32_t count, ANM_REGION **reg)
{
uint32_t *ofsbuf;
ANM_REGION *regbuf;
uint32_t i;

if(count == 0) return 0;

ofsbuf = malloc(count * sizeof(uint32_t));
if(!ofsbuf) {
perror("malloc");
return 1;
}
if(fread(ofsbuf, sizeof(uint32_t), count, fp) != count) {
if(ferror(fp)) perror("fread");
else fprintf(stderr, "error : file may be corrupted\n");
return 1;
}
regbuf = malloc(count * sizeof(ANM_REGION));
if(!regbuf) {
perror("malloc");
free(ofsbuf);
return 1;
}
for(i = 0; i < count; ++i) {
if(fseek(fp, baseofs + ofsbuf, SEEK_SET)) {
perror("fseek");
free(regbuf);
free(ofsbuf);
return 1;
}
if(fread(regbuf + i, sizeof(ANM_REGION), 1, fp) != 1) {
if(ferror(fp)) perror("fread");
else fprintf(stderr, "error : file may be corrupted\n");
free(regbuf);
free(ofsbuf);
return 1;
}
}

*reg = regbuf;
return 0;
}

int read_cstr(char *buf, int max, FILE *fp)
{
int i, c = -1;
for(i = 0; i < (max - 1) && c; ++i) {
c = fgetc(fp);
if(c == EOF) {
if(ferror(fp)) return -2;
if(feof(fp)) return -1;
return -3;
}
buf = c;
}
buf = 0;
return i;
}

void remap_header_th11(ANM_ENTRY_HEADER *anm)
{
ANM_ENTRY_HEADER_TH11 nanm;
memcpy(&nanm, anm, sizeof(nanm));
anm->attrnum = nanm.attrnum;
anm->regnum = nanm.regnum;
anm->width = nanm.width;
anm->height = nanm.height;
anm->nameofs = nanm.nameofs;
anm->version = nanm.version;
anm->entofs = nanm.entofs;
anm->nextofs = nanm.nextofs;
}

int main(int argc, char *argv[])
{
FILE *fp;
ANM_ENTRY_HEADER anm;
ANM_THTX_HEADER thtx;
ANM_REGION *regbuf;
char name[_MAX_PATH];
char *filename;
char *entbuf;
long filelen;
long namelen;
uint32_t i;
uint32_t baseofs;

if (argc != 2) {
printf(
"usage: anm2png FILE\n"
"Convert Touhou Animation FILE to PNG\n");
return EXIT_SUCCESS;
}

fp = fopen(argv[1], "rb");
if(fp == NULL) {
perror("fopen");
return EXIT_FAILURE;
}
if(fseek(fp, 0, SEEK_END)) {
perror("fseek");
return EXIT_FAILURE;
}
if((filelen = ftell(fp)) == -1) {
perror("ftell");
return EXIT_FAILURE;
}
rewind(fp);

baseofs = 0x0;
do {
/* ?????? */
if(fseek(fp, baseofs, SEEK_SET)) {
perror("fseek");
return EXIT_FAILURE;
}
if(fread(&anm, 0x40, 1, fp) != 1) {
if(ferror(fp)) perror("fread");
else fprintf(stderr, "error : file may be corrupted\n");
return EXIT_FAILURE;
}
/* ????????? */
if(anm.version != 2 && anm.version != 3 && anm.version != 4) {
remap_header_th11(&anm);
if(anm.version != 0x7) {
fprintf(stderr, "error : version not supported. version: %d\n", anm.version);
return EXIT_FAILURE;
}
}
/* ???????????? */
regbuf = NULL;
if(read_region_info(fp, baseofs, anm.regnum, &regbuf)) {
return EXIT_FAILURE;
}
/* ?????????????? */
/* if(read_attribute(fp, baseofs, anm.attrnum, &attrbuf)) {
return EXIT_FAILURE;
} */
/* ?????????? */
if(fseek(fp, baseofs + anm.nameofs, SEEK_SET)) {
perror("fseek");
return EXIT_FAILURE;
}
namelen = read_cstr(name, _MAX_PATH, fp);
if(namelen < 0) {
if(namelen != -1) perror("read_cstr");
else fprintf(stderr, "error : file may be corrupted\n");
return EXIT_FAILURE;
}

/* ???????????? */
if(fseek(fp, baseofs + anm.entofs, SEEK_SET)) {
perror("fseek");
return EXIT_FAILURE;
}
if(fread(&thtx, sizeof(thtx), 1, fp) != 1) {
perror("fread");
return EXIT_FAILURE;
}

if(thtx.magic == 'XTHT' && (thtx.type == 1 || thtx.type == 3 || thtx.type == 5)) {
/* ?????????? */
entbuf = malloc(thtx.size);
if(!entbuf) {
perror("malloc");
return EXIT_FAILURE;
}
if(fread(entbuf, thtx.size, 1, fp) != 1) {
if(ferror(fp)) perror("fread");
else fprintf(stderr, "error : file may be corrupted\n");
return EXIT_FAILURE;
}
/* ????????? */
printf("----------------\n");
printf("Filename: %s\n", name);
printf("Type : %s\n",
thtx.type == 1 ? "1/BGRA8888":
thtx.type == 3 ? "3/BGR565":
thtx.type == 5 ? "5/BGRA4444":
"unknown");
printf("Size : %d x %d\n", thtx.width, thtx.height);
printf("Regions :\n");
for(i = 0; i < anm.regnum; ++i) {
printf("ID: %08x (%.f,%.f)-Step(%.f,%.f)\n",
regbuf.id,
regbuf.left, regbuf.top,
regbuf.right, regbuf.bottom);
}
/* ?????????? */
filename = strrchr(name, '/');
if(filename != NULL) ++filename;
else filename = name;

printf("Converting...\n", name);
thtx_to_png(&thtx, entbuf, filename);
free(entbuf);
}
free(regbuf);

baseofs += anm.nextofs;
} while (anm.nextofs);

fclose(fp);
}/*

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I have tried using headers from zlib and libpng, but I get errors (it seems I'm still missing some headers?). will anyone who is capable of compiling this source code please direct me to the exact references for which I can get the proper headers/libraries? I am using Microsoft Visual Studio C++ Professional.
Help very much appreciated.

Maybe if you told us the errors you were getting, we could tell you what headers/libraries you're missing. Just an idea.  But I'm gonna guess you probably aren't linking to a library.

I have triple checked, the libraries are all linked.
This is my error- fatal error C1083: Cannot open include file: 'unistd.h': No such file or directory

I installed zlib and libpng from sourceforge. These are the links.
http://sourceforge.net/projects/gnuwin32/files/zlib/1.2.3/zlib-1.2.3.exe/download?use_mirror=superb-dca2
http://sourceforge.net/projects/gnuwin32/files/libpng/1.2.37/libpng-1.2.37-setup.exe/download

Both the include and header files are linked, but it seems I got the wrong set? I'm not sure, I'm still trying to figure this out. I honestly thought getting zlib/libpng would be a trivial matter. Why isn't it working?
Can someone try to compile it and tell me where I went wrong?