Merge pull request #754 from Kijewski/pthread_reaper_stack-linkage

`pthread_reaper_stack` has global linkage for no proper reason.
test: added missing license
Merge pull request #761 from mehlis/test-pthread-license

test: added missing license
Add toolchain script for x86
First x86-multiboot commit
Use i586 (Pentium) instead of i486 toolchain
Implement getcontext and setcontext
Interrupt handling should be working, now
Less magic numbers for UART
Implement PIC
'Implement' GDT and PIT, fix PIC
Add page table (no #PF handler, yet)
Dump
Page fault handler works now
Fix inISR() tracking
Add FPU support
Implement RTC
Fix thread_yield() bug (didn't restore EFLAGS.IF)
Newlib mallocs pages before x86_init_memory gets called
Implement PCI (listing only)