I faced something stranger, I ask for help from good people. I use windows 10, g++ compiler, visual studio code. i tried moving g++.exe itself to another directory, tried run with --verbose and -W, it doesn't help. Im trying to make almost empty project:

#include <stddef.h>
#include <windows.h>
#include "glut.h"


int main(){
    return 0;
}

glut files version 3.7.6, gl.h and glu.h from windows SDK 10.0.26100.0 for windows 10.

my tasks.json:

{
    "tasks": [
        {
            "type": "cppbuild",
            "label": "C/C++: g++.exe build active file",
            "command": "c://temporarygcc//ucrt64//bin//g++.exe",
            "args": [
                "-fdiagnostics-color=always",
                "-g",
                "${file}",
                "${workspaceFolder}//glut32.lib",
                "${workspaceFolder}//glut32.dll",
                "${workspaceFolder}//glut.def",
                "${workspaceFolder}//glut.h",
                
                "-o",
                "${fileDirname}\\${fileBasenameNoExtension}.exe"
            ],
            "options": {
                "cwd": "${fileDirname}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "detail": "Task generated by Debugger."
        }
    ],
    "version": "2.0.0"
}

First error:

Starting build...
cmd /c chcp 65001>nul && c://temporarygcc//ucrt64//bin//g++.exe -fdiagnostics-color=always -g C:\Users\leonid\Desktop\vsccp\program.cpp C:\Users\leonid\Desktop\vsccp//glut32.lib C:\Users\leonid\Desktop\vsccp//glut32.dll C:\Users\leonid\Desktop\vsccp//glut.def C:\Users\leonid\Desktop\vsccp//glut.h -o C:\Users\leonid\Desktop\vsccp\program.exe
C:/Users/leonid/Desktop/vsccp/glut.h:50:24: error: redeclaration of C++ built-in type 'wchar_t' [-fpermissive]
   50 | typedef unsigned short wchar_t;
      |                        ^~~~~~~

Build finished with error(s).

then I rename wchar_t -> wchar_tt

what i get:

Starting build...
cmd /c chcp 65001>nul && c://temporarygcc//ucrt64//bin//g++.exe -fdiagnostics-color=always -g C:\Users\leonid\Desktop\vsccp\program.cpp C:\Users\leonid\Desktop\vsccp//glut32.lib C:\Users\leonid\Desktop\vsccp//glut32.dll C:\Users\leonid\Desktop\vsccp//glut.def C:\Users\leonid\Desktop\vsccp//glut.h -o C:\Users\leonid\Desktop\vsccp\program.exe
collect2.exe: error: ld returned 5 exit status

Build finished with error(s).

if I run it with gcc program.cpp glut.h glut32.lib glut32.dll --verbose i get this:

C:/msys64/ucrt64/include/GL/glu.h:25:7: error: unknown type name 'wchar_t'
   25 | const wchar_t *APIENTRY gluErrorUnicodeStringEXT(GLenum errCode);
      |       ^~~~~~~
C:/msys64/ucrt64/include/GL/glu.h:1:1: note: 'wchar_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
  +++ |+#include <stddef.h>
    1 | /**

than I go right into C:/msys64/ucrt64/include/GL/glu.h and add #include <stddef.h> to the first line of file. Run again and get:

C:/msys64/ucrt64/include/GL/glu.h:27:7: error: unknown type name 'wchar_t'
   27 | const wchar_t *APIENTRY gluErrorUnicodeStringEXT(GLenum errCode);
      |       ^~~~~~~
C:/msys64/ucrt64/include/GL/glu.h:7:1: note: 'wchar_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
    6 | #include <stddef.h>
  +++ |+#include <stddef.h>
    7 |

what is my next move?

UPD:

when I use cl.exe instead of g++.exe , it ignores wchar_t problem, and compiles program without single error. What why ?