Do not use print colored help if stdout is not a TTY

src/libvlc.c

@@ -1328,9 +1328,10 @@ static void Usage( libvlc_int_t *p_this, char const *psz_module_name )
     psz_spaces_text[PADDING_SPACES+LINE_START] = '\0';
     memset( psz_spaces_longtext, ' ', LINE_START+2 );
     psz_spaces_longtext[LINE_START+2] = '\0';
-#ifdef WIN32
-    b_color = false; // don't put color control codes in a .txt file
+#ifndef WIN32
+    if( !isatty( 1 ) )
 #endif
+        b_color = false; // don't put color control codes in a .txt file
 
     if( b_color )
     {