There are extensions to 386 psABI:

https://groups.google.com/forum/#!topic/ia32-abi/awsRSvJOJfs

to call tls_get_addr via GOT:

call *___tls_get_addr@GOT(%reg)

where EBX register isn't required as GOT base.

Since direct call is 4-byte long and indirect call, is 5-byte long, the
extra one byte must be handled properly.

For general dynamic model, 7-byte lea instruction before call
instruction is replaced by 6-byte one to make room for indirect call.
For local dynamic model, we simply use 5-byte indirect call.

TLS linker optimization is updated to recognize new instruction
patterns.  For local dynamic model to local exec model transition,
we generate a 6-byte lea instruction as nop, instead of a 1-byte nop
plus a 4-byte lea instruction.

	PR gold/20308
	* i386.cc (Target_i386::Relocate::relocate): Allow
	R_386_GOT32X relocation against ___tls_get_addr.
	(Target_i386::Relocate::tls_gd_to_ie): Support indirect
	call to __tls_get_addr.
	(Target_i386::Relocat...