gold: Support 386 TLS code sequences without PLT

gold: Support 386 TLS code sequences without PLT

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::Relocate::tls_gd_to_le): Likewise.
	(Target_i386::Relocate::tls_ld_to_le): Likewise.
	* testsuite/Makefile.am (check_PROGRAMS): Add pr20308a_test,
	pr20308b_test, pr20308c_test, pr20308d_test, pr20308e_test.
	(pr20308a_test_SOURCES): New.
	(pr20308a_test_DEPENDENCIES): Likewise.
	(pr20308a_test_CFLAGS): Likewise.
	(pr20308a_test_LDFLAGS): Likewise.
	(pr20308a_test_LDADD): Likewise.
	(pr20308b_test_SOURCES): Likewise.
	(pr20308b_test_DEPENDENCIES): Likewise.
	(pr20308b_test_CFLAGS): Likewise.
	(pr20308b_test_LDFLAGS): Likewise.
	(pr20308b_test_LDADD): Likewise.
	(pr20308c_test_SOURCES): Likewise.
	(pr20308c_test_DEPENDENCIES): Likewise.
	(pr20308c_test_CFLAGS): Likewise.
	(pr20308c_test_LDFLAGS): Likewise.
	(pr20308c_test_LDADD): Likewise.
	(pr20308d_test_SOURCES): Likewise.
	(pr20308d_test_DEPENDENCIES): Likewise.
	(pr20308d_test_CFLAGS): Likewise.
	(pr20308d_test_LDFLAGS): Likewise.
	(pr20308d_test_LDADD): Likewise.
	(pr20308e_test_SOURCES): Likewise.
	(pr20308e_test_DEPENDENCIES): Likewise.
	(pr20308e_test_CFLAGS): Likewise.
	(pr20308e_test_LDFLAGS): Likewise.
	(pr20308e_test_LDADD): Likewise.
	(pr20308a.so): Likewise.
	(pr20308b.so): Likewise.
	(pr20308_gd.o): Likewise.
	(pr20308_ld.o): Likewise.
	(MOSTLYCLEANFILES): Add pr20308a.so pr20308b.so.
	* testsuite/Makefile.in: Regenerated.
	* testsuite/pr20308_def.c: New file.
	* testsuite/pr20308_gd.S: Likewise.
	* testsuite/pr20308_ld.S: Likewise.
	* testsuite/pr20308_main.c: Likewise.