Handle void * conversions in FreeBSD/x86 native code to fix C++ build.
    
    gdb/ChangeLog:
    
    	* amd64bsd-nat.c (amd64bsd_fetch_inferior_registers): Change xstateregs
    	to void *.
    	(amd64bsd_store_inferior_registers): Likewise.
    	* fbsd-nat.c (resume_one_thread_cb): Explicitly cast data to ptid_t *.
    	(resume_all_threads_cb): Likewise.
    	* i386bsd-nat.c (i386bsd_supply_gregset): Cast gregs to char *.
    	(i386bsd_collect_gregset): Likewise.
    	(i386bsd_fetch_inferior_registers): Change xstateregs to void *.
    	(i386bsd_store_inferior_registers): Likewise.