fix non-PIC relocation in 32-bit dso thunk

Related to #3187 which fixes text relocations for X86_64 PIC code.
This one fixes text relocations in the X86_32 DSO startup code.
Also see [Issue 11171 – Text relocations in Phobos shared library](https://d.puremagic.com/issues/show_bug.cgi?id=11171).