libctf warnings

Seen with every compiler I have if using -fno-inline:
home/alan/src/binutils-gdb/libctf/ctf-create.c: In function ‘ctf_add_encoded’:
/home/alan/src/binutils-gdb/libctf/ctf-create.c:555:3: warning: ‘encoding’ may be used uninitialized [-Wmaybe-uninitialized]
  555 |   memcpy (dtd->dtd_vlen, &encoding, sizeof (encoding));

Seen with gcc-4.9 and probably others at lower optimisation levels:
home/alan/src/binutils-gdb/libctf/ctf-serialize.c: In function 'symtypetab_density':
/home/alan/src/binutils-gdb/libctf/ctf-serialize.c:211:18: warning: 'sym' may be used uninitialized in this function [-Wmaybe-uninitialized]
    if (*max < sym->st_symidx)

Seen with gcc-4.5 and probably others at lower optimisation levels:
/home/alan/src/binutils-gdb/libctf/ctf-types.c:1649:21: warning: 'tp' may be used uninitialized in this function
/home/alan/src/binutils-gdb/libctf/ctf-link.c:765:16: warning: 'parent_i' may be used uninitialized in this function

Also with gcc-4.5:
In file included from /home/alan/src/binutils-gdb/libctf/ctf-endian.h:25:0,
                 from /home/alan/src/binutils-gdb/libctf/ctf-archive.c:24:
/home/alan/src/binutils-gdb/libctf/swap.h:70:0: warning: "_Static_assert" redefined
/usr/include/sys/cdefs.h:568:0: note: this is the location of the previous definition

	* swap.h (_Static_assert): Don't define if already defined.
	* ctf-serialize.c (symtypetab_density): Merge two
	CTF_SYMTYPETAB_FORCE_INDEXED blocks.
	* ctf-create.c (ctf_add_encoded): Avoid "encoding" may be used
	uninitialized warning.
	* ctf-link.c (ctf_link_deduplicating_open_inputs): Avoid
	"parent_i" may be used uninitialized warning.
	* ctf-types.c (ctf_type_rvisit): Avoid "tp" may be used
	uninitialized warning.

libctf/ctf-types.c

@@ -1646,7 +1646,7 @@ ctf_type_rvisit (ctf_dict_t *fp, ctf_id_t type, ctf_visit_f *func,
 {
   ctf_dict_t *ofp = fp;
   ctf_id_t otype = type;
-  const ctf_type_t *tp;
+  const ctf_type_t *tp = NULL;
   const ctf_dtdef_t *dtd;
   unsigned char *vlen;
   ssize_t size, increment, vbytes;