WINGDIAPI not defined

I’m trying to run a simple openGL program, but I’m getting the following error as a result of the line

#include <gl/gl.h>

The error is:

Error E2141 c:\Borland\Bcc55\include\gl\gl.h 1153: Declaration syntax error
Error E2238 c:\Borland\Bcc55\include\gl\gl.h 1154: Multiple declaration for ‘WINGDIAPI’
Error E2344 c:\Borland\Bcc55\include\gl\gl.h 1153: Earlier declaration of ‘WINGDIAPI’

This error actually repeats for every line in gl.h until 1161 where it bails out because of too many errors. If you look in gl.h, starting at line 1153, there’s a bunch of function declarations. Here’s the first three as an example:

WINGDIAPI void APIENTRY glAccum (GLenum op, GLfloat value);
WINGDIAPI void APIENTRY glAlphaFunc (GLenum func, GLclampf ref);
WINGDIAPI GLboolean APIENTRY glAreTexturesResident (GLsizei n, const GLuint *textures, GLboolean *residences);

and this goes on 'till line 1488. I ran a search throughout the whole file for anything like “#define WINGDIAPI” and any “#include” but came up short.

What could be the problem?

Try including windows.h before gl.h