gdb/

gdb/
	Fix disp-step-syscall.exp: fork: single step over fork.
	* i386-linux-tdep.c (-i386_linux_get_syscall_number): Rename to ...
	(i386_linux_get_syscall_number_from_regcache): ... here, new function
	comment, change parameters gdbarch and ptid to regcache.  Remove
	parameter regcache, initialize gdbarch from regcache here.
	(i386_linux_get_syscall_number, i386_linux_displaced_step_copy_insn):
	New functions.
	(i386_linux_init_abi): Install i386_linux_displaced_step_copy_insn
	instead.
	* i386-tdep.c (i386_syscall_p): Check also for 'sysenter' and
	'syscall'.  Make the 'int' check more strict.

gdb/testsuite/
	Fix disp-step-syscall.exp: fork: single step over fork.
	* gdb.base/disp-step-syscall.exp (syscall_insn): Anchor it by
	whitespaces.
	(single step over $syscall): Remove its check.
	(single step over $syscall final pc): New check.