The ebtables code relies on the `-nostartfiles` linker argument to execute the
extension modules' `_init()` functions automatically which is not working
reliably across all supported targets and gcc versions.
Running an ebtables executable linked this way just crashes with a segmentation
fault at runtime on program startup, e.g. on ARM architectures.
In order to fix the issue ...
- remove the use of the -nostartfiles linker flag
- rename the init procedures to a generic name without implicit semantics
- explicitely annotate those init procedures as constructors
The patch has been taken from the Alpine Linux distribution at
http://git.alpinelinux.org/cgit/aports/tree/main/ebtables/fix-extension-init.patch
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
