This is enough to get thru a cross-build.

gnu/usr.bin/binutils/gdb/alpha/freebsd-nat-stubs.c

@@ -0,0 +1,55 @@
+/* $FreeBSD$ */
+
+#include "defs.h"
+
+/* Size of elements in jmpbuf */
+
+#define JB_ELEMENT_SIZE 8
+
+#define JB_PC 2
+
+int kernel_debugging = 0;
+
+fetch_kcore_registers (pcbp)
+  struct pcb *pcbp;
+{
+  return;
+}
+
+void
+fetch_inferior_registers (regno)
+     int regno;
+{
+  return;
+}
+
+void
+store_inferior_registers (regno)
+     int regno;
+{
+  return;
+}
+
+/* From gdb/alpha-nat.c.  */
+
+/* Figure out where the longjmp will land.
+   We expect the first arg to be a pointer to the jmp_buf structure from which
+   we extract the pc (JB_PC) that we will land at.  The pc is copied into PC.
+   This routine returns true on success. */
+
+int
+get_longjmp_target (pc)
+     CORE_ADDR *pc;
+{
+  CORE_ADDR jb_addr;
+  char raw_buffer[MAX_REGISTER_RAW_SIZE];
+
+  jb_addr = read_register(A0_REGNUM);
+
+  if (target_read_memory(jb_addr + JB_PC * JB_ELEMENT_SIZE, raw_buffer,
+			 sizeof(CORE_ADDR)))
+    return 0;
+
+  *pc = extract_address (raw_buffer, sizeof(CORE_ADDR));
+  return 1;
+}