Add more doc for avaialbe options for USE_LIBBACKTRACE

Author: yelite

cmake/modules/Logging.cmake

@@ -68,7 +68,14 @@ macro(__compile_libbacktrace)
   set(LIBBACKTRACE_FOUND YES)
 endmacro()
 
-
+# Available options for USE_LIBBACKTRACE:
+# - OFF: Don't use libbacktrace
+# - ON: Find libbacktrace from system paths. Fail the build generation if libbacktrace is not found.
+# - COMPILE: Build and link to libbacktrace from 3rdparty/libbacktrace. 
+# - <PATH>: Looking for the libbacktrace header and static lib from a user-provided path. Fail the build generation if libbacktrace is not found.
+# - AUTO: 
+#   - Find libbacktrace from system paths.
+#   - If not found, fallback to COMPILE on Linux or MacOS, fallback to OFF on Windows.
 if(USE_LIBBACKTRACE STREQUAL "AUTO")
   __find_libbacktrace()
   if(NOT LIBBACKTRACE_FOUND AND (CMAKE_SYSTEM_NAME MATCHES "Linux" OR CMAKE_SYSTEM_NAME MATCHES "Darwin"))