include guard

Posted Oct 1, 2017 19:44 UTC (Sun) by Jandar (subscriber, #85683)
In reply to: C, still? by philomelus
Parent article: Building the kernel with Clang

For more than a decade gcc recognizes an include guard and doesn't open the file a second time.

https://gcc.gnu.org/onlinedocs/cppinternals/Guard-Macros....