gdb: Fix x86_64 build with NDK r16

The NDK headers now define elf_siginfo.

packages/gdb/bfd-hosts-x86-64linux.h.patch

@@ -1,19 +0,0 @@
-diff -u -r ../gdb-7.11.1/bfd/hosts/x86-64linux.h ./bfd/hosts/x86-64linux.h
---- ../gdb-7.11.1/bfd/hosts/x86-64linux.h	2016-02-09 22:19:39.000000000 -0500
-+++ ./bfd/hosts/x86-64linux.h	2016-06-17 16:57:30.815715258 -0400
-@@ -32,6 +32,15 @@
- /* We define here only the symbols differing from their 64-bit variant.  */
- #include <sys/procfs.h>
- 
-+#ifdef __ANDROID__
-+struct elf_siginfo {
-+	int si_signo;
-+	int si_code;
-+	int si_errno;
-+};
-+#define ELF_PRARGSZ (80)
-+#endif
-+
- #ifdef HAVE_STDINT_H
- #include <stdint.h>
- #else