Don't declare xmalloc or xrealloc in bucomm.h

It's better to include the proper header, which has declarations with
various attributes.  Commit 096aefc040 in 1994 introduced this wart.

	* bucomm.h (xmalloc, xrealloc): Delete declaration.
	* od-macho.c: Include libiberty.h.
	* od-xcoff.c: Include libiberty.h.

binutils/bucomm.h

@@ -76,12 +76,6 @@ extern void set_times (const char *, const struct stat *);
 extern int smart_rename (const char *, const char *, int,
 			 struct stat *, bool);
 
-
-/* In libiberty.  */
-void *xmalloc (size_t);
-
-void *xrealloc (void *, size_t);
-
 #if __GNUC__ >= 7
 #define _mul_overflow(a, b, res) __builtin_mul_overflow (a, b, res)
 #else

binutils/od-macho.c

@@ -23,6 +23,7 @@
 #include <stddef.h>
 #include <time.h>
 #include "safe-ctype.h"
+#include "libiberty.h"
 #include "bfd.h"
 #include "objdump.h"
 #include "bucomm.h"

binutils/od-xcoff.c

@@ -23,6 +23,7 @@
 #include <stddef.h>
 #include <time.h>
 #include "safe-ctype.h"
+#include "libiberty.h"
 #include "bfd.h"
 #include "objdump.h"
 #include "bucomm.h"