fix 879 - support for --gc-sections

[MartinNowak]

• pin .deh_eh and .minfo by emitting fake references in dso startup code
• enable --gc-sections linker switch

Issue 879 - support for --gc-sections

[WalterBright]

If this only works on Linux, it's still worth pulling, as long as the old behavior is used on other platforms rather than them failing.

[MartinNowak]

OK @WalterBright , updated the pull to only be active on linux.

[MartinNowak]

Changed to use R_arch_NONE relocations.

[MartinNowak]

Changed to use R_arch_NONE relocations.

[MartinNowak]

FYI @Dicebot

[mihails-strasuns]

Description looks AWESOME :)
Bookmarked, going to experiment with it next weekend.

[mihails-strasuns]

Does not seem to make any actual effect. Using this trivial snippet:

void foo2()
{
}

void foo1()
{
    foo2();
}

void main()
{
}

nm a.out | grep foo shows that unused functions are still present in the binary :(