[Windows] Enable crash reporter on MinGW builds, use libbacktrace to generate stack trace from DWARF symbols.

drivers/backtrace/SCsub

@@ -0,0 +1,44 @@
+#!/usr/bin/env python
+
+Import("env")
+
+env_backtrace = env.Clone()
+
+# Thirdparty source files
+
+thirdparty_obj = []
+
+thirdparty_dir = "#thirdparty/libbacktrace/"
+thirdparty_sources = [
+    "atomic.c",
+    "dwarf.c",
+    "fileline.c",
+    "posix.c",
+    "print.c",
+    "sort.c",
+    "state.c",
+    "backtrace.c",
+    "simple.c",
+    "pecoff.c",
+    "read.c",
+    "alloc.c",
+]
+thirdparty_sources = [thirdparty_dir + file for file in thirdparty_sources]
+
+env_backtrace.Prepend(CPPPATH=[thirdparty_dir])
+
+env_thirdparty = env_backtrace.Clone()
+env_thirdparty.disable_warnings()
+env_thirdparty.add_source_files(thirdparty_obj, thirdparty_sources)
+
+env.drivers_sources += thirdparty_obj
+
+# Godot source files
+
+driver_obj = []
+
+env_backtrace.add_source_files(driver_obj, "*.cpp")
+env.drivers_sources += driver_obj
+
+# Needed to force rebuilding the driver files when the thirdparty library is updated.
+env.Depends(driver_obj, thirdparty_obj)