release: include error metadata file for launcher purposes (#1463)

* release: include error metadata file for launcher purposes

* release: put release assets in the top level of the 7z/tarball (no out/ dir)

* extractor: ensure critical directories are created

* extractor: handle weird Win32 path prefix `\\?\` by stripping it out

* release: avoid using `-C` with `tar`

common/log/log.cpp

@@ -9,6 +9,7 @@
 #include <Windows.h>
 #endif
 #include "common/util/Assert.h"
+#include "common/util/FileUtil.h"
 
 namespace lg {
 struct Logger {
@@ -79,6 +80,7 @@ void log_message(level log_level, LogTime& now, const char* message) {
 
 void set_file(const std::string& filename) {
   ASSERT(!gLogger.fp);
+  file_util::create_dir_if_needed_for_file(filename);
   gLogger.fp = fopen(filename.c_str(), "w");
   ASSERT(gLogger.fp);
 }