Move main bootstrap to platform-specific object

To prevent multiple execution of main-bootstrap, I moved the code to a
statically initialized object. The reason for this change is that
_main() is exeuted twice when starting dynamic binaries. Now, the object
is part of the base-common library which is linked with ld.lib.so.

Also fixes #883.
Increase quota of lwip_lx.run

See 33909779 for documentation.