shawn@shawn-VGN-CR120E:~/stereograph-0.30a$ make
gcc -Wall -O2 -Dlinux   -c -o gfxio.o gfxio.c
gfxio.c: In function ‘Resize_GFX’:
gfxio.c:104:4: warning: implicit declaration of function ‘memcpy’ [-Wimplicit-function-declaration]
    memcpy(temp_gfx + y * width, gfx->Data + gfx->Width * y, width*sizeof(int));
    ^~~~~~
gfxio.c:104:4: warning: incompatible implicit declaration of built-in function ‘memcpy’
gfxio.c:104:4: note: include ‘<string.h>’ or provide a declaration of ‘memcpy’
gfxio.c: In function ‘Write_Gfx_File’:
gfxio.c:237:7: warning: implicit declaration of function ‘strlen’ [-Wimplicit-function-declaration]
    if(strlen(file_name) >= 4) {
       ^~~~~~
gfxio.c:237:7: warning: incompatible implicit declaration of built-in function ‘strlen’
gfxio.c:237:7: note: include ‘<string.h>’ or provide a declaration of ‘strlen’
gfxio.c:238:9: warning: implicit declaration of function ‘strcmp’ [-Wimplicit-function-declaration]
     if(!strcmp(file_name + strlen(file_name) - 4, ".tga"))
         ^~~~~~
gfxio.c: In function ‘Read_PPM’:
gfxio.c:331:4: warning: this ‘while’ clause does not guard... [-Wmisleading-indentation]
    while(isspace(a = fgetc(ifile))); ungetc(a, ifile);
    ^~~~~
gfxio.c:331:38: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the ‘while’
    while(isspace(a = fgetc(ifile))); ungetc(a, ifile);
                                      ^~~~~~
gfxio.c:333:4: warning: this ‘while’ clause does not guard... [-Wmisleading-indentation]
    while(isspace(a = fgetc(ifile))); ungetc(a, ifile);
    ^~~~~
gfxio.c:333:38: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the ‘while’
    while(isspace(a = fgetc(ifile))); ungetc(a, ifile);
                                      ^~~~~~
gfxio.c:335:4: warning: this ‘while’ clause does not guard... [-Wmisleading-indentation]
    while(isspace(a = fgetc(ifile))); ungetc(a, ifile);
    ^~~~~
gfxio.c:335:38: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the ‘while’
    while(isspace(a = fgetc(ifile))); ungetc(a, ifile);
                                      ^~~~~~
gfxio.c:339:3: warning: this ‘while’ clause does not guard... [-Wmisleading-indentation]
   while(isspace(a = fgetc(ifile))); ungetc(a, ifile);
   ^~~~~
gfxio.c:339:37: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the ‘while’
   while(isspace(a = fgetc(ifile))); ungetc(a, ifile);
                                     ^~~~~~
In file included from /usr/include/pngconf.h:50:0,
                 from /usr/include/png.h:364,
                 from gfxio.c:26:
gfxio.c: In function ‘Write_PNG’:
gfxio.c:493:20: error: dereferencing pointer to incomplete type ‘png_struct {aka struct png_struct_def}’
  if (setjmp(png_ptr->jmpbuf)) {
                    ^
gfxio.c: In function ‘Read_TARGA’:
gfxio.c:536:2: warning: incompatible implicit declaration of built-in function ‘memcpy’
  memcpy(header, check_header, sizeof(char)*8);
  ^~~~~~
gfxio.c:536:2: note: include ‘<string.h>’ or provide a declaration of ‘memcpy’
In file included from gfxio.c:21:0:
gfxio.c: In function ‘Write_TARGA’:
gfxio.c:697:7: warning: incompatible implicit declaration of built-in function ‘strlen’
  putc(strlen("created by stereograph"), ofile);
       ^
gfxio.c:697:7: note: include ‘<string.h>’ or provide a declaration of ‘strlen’
<builtin>: recipe for target 'gfxio.o' failed
make: *** [gfxio.o] Error 1
shawn@shawn-VGN-CR120E:~/stereograph-0.30a$