[strongSwan] why not use gcc extension to facilitate us

[Shengju Zhang]

Dear,

I find lots of function calls of 'library_init' or 'libhydra_init'
etc. in the source code.
why don't we just use the GCC extension '__attribute__
((constructor))' and '__attribute__((destructor))' to facilitate our
work?
Is there any other concerns?

Thanks,
Sean.