glewInit() 失败与 "Missing GL version" ， SDL2 OpenGL 上下文， cygwin 编译器

下面的程序创建了一个窗口，该窗口除了在按esc时关闭外什么都不做。当我用cygwin编译它时，没有任何错误。我使用的GLEW来自Cygwin Ports，SDL2版本为2.0.3，来自他们网站的SDL2-devel-2.0.3-mingw.tar.gz下载。我在编译的可执行文件的目录中有SDL2.dll。

链接到：-lSDL2 -lSDL2main -lGLEW -lGLU -lGL -lSDL2 -lSDL2main -lGLEW -lGLU -lGL，两次以确保所有内容都已链接。

还编译有：-std=c++11

在我的电脑上，打印出以下程序：

OpenGL Vendor: (null)
OpenGL Renderer: (null)
OpenGL Shading Language Version: (null)
OpenGL Extensions: (null)
Error initializing GLEW! Missing GL version

程序似乎不起作用。主要的问题是，如果我尝试调用，例如glGenVertexArrays，程序将与STATUS_ACCESS_VIOLATION一起崩溃。（请参阅此处的崩溃代码。我认为这与GLEW的错误Missing GL version有关。

#include <cstdio>
#include <chrono>
#include <thread>
#include <SDL2/SDL.h>
#include <GL/glew.h>
#include <SDL2/SDL_opengl.h>
#include <GL/glu.h>
const int width = 1000;
const int height = 500;
bool Running = true;
#undef main
int main (int argc, char *argv[]) {
    FILE* cdebug = fopen("cdebug.txt", "w");
    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        fprintf(cdebug, "SDL could not initialize! SDL Error: %sn", SDL_GetError()); fflush(cdebug);
    }
    #define setAttr(attr, value) 
        if (SDL_GL_SetAttribute(attr, value) < 0) { 
            fprintf(cdebug, "SDL failed to set %s to %s, SDL Error: %sn", #attr, #value, SDL_GetError()); fflush(cdebug);
        }
    setAttr(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    setAttr(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    setAttr(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    setAttr(SDL_GL_RED_SIZE, 8);
    setAttr(SDL_GL_GREEN_SIZE, 8);
    setAttr(SDL_GL_BLUE_SIZE, 8);
    setAttr(SDL_GL_DEPTH_SIZE, 24);
    setAttr(SDL_GL_DOUBLEBUFFER, 1);
    #undef setAttr
    /*
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
    SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
    SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
    */
    SDL_Window *window = SDL_CreateWindow(
            "test",
            SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
            640, 480,
            SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE
    );
    if (window == NULL) {
        fprintf(cdebug, "Window could not be created! SDL Error: %sn", SDL_GetError()); fflush(cdebug);
    }
    SDL_GLContext GLContext = SDL_GL_CreateContext(window);
    if (GLContext == NULL) {
        fprintf(cdebug, "OpenGL context could not be created! SDL Error: %sn", SDL_GetError()); fflush(cdebug);
    }
    if (SDL_GL_MakeCurrent(window, GLContext) < 0) {
        fprintf(cdebug, "OpenGL context could not be made current! SDL Error: %sn", SDL_GetError()); fflush(cdebug);
    }
    fprintf(cdebug, "OpenGL Vendor: %sn", glGetString(GL_VENDOR));
    fprintf(cdebug, "OpenGL Renderer: %sn", glGetString(GL_RENDERER));
    fprintf(cdebug, "OpenGL Shading Language Version: %sn", glGetString(GL_SHADING_LANGUAGE_VERSION));
    fprintf(cdebug, "OpenGL Extensions: %sn", glGetString(GL_EXTENSIONS));
    fflush(cdebug);
    glewExperimental = GL_TRUE;
    {
        GLenum glewError = glewInit();
        if (glewError != GLEW_OK) {
            fprintf(cdebug, "Error initializing GLEW! %sn", glewGetErrorString(glewError)); fflush(cdebug);
        }
    }
    SDL_Event event;
    while (Running) {
        while (SDL_PollEvent(&event)) {
            switch (event.type) {
                case SDL_KEYUP: {
                    switch (event.key.keysym.scancode) {
                        case SDL_SCANCODE_ESCAPE:
                            Running = false;
                            break;
                    }
                    break;
                }
            }
        }
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        SDL_GL_SwapWindow(window);
        std::this_thread::sleep_for(std::chrono::milliseconds(50));
    }
    SDL_GL_DeleteContext(GLContext);
    SDL_DestroyWindow(window);
    window = NULL;
    SDL_Quit();
    return 0;
}