progs/trivial: add fflushes for cygwin
diff --git a/progs/trivial/tri-userclip.c b/progs/trivial/tri-userclip.c
index 43d19ce..8f37e0f 100644
--- a/progs/trivial/tri-userclip.c
+++ b/progs/trivial/tri-userclip.c
@@ -41,6 +41,7 @@
fprintf(stderr, "GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
fprintf(stderr, "GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
fprintf(stderr, "GL_VENDOR = %s\n", (char *) glGetString(GL_VENDOR));
+ fflush(stderr);
glClearColor(0.0, 0.0, 1.0, 0.0);
glClipPlane(GL_CLIP_PLANE0, plane);