gdb: Use std::min and std::max throughout

gdb: Use std::min and std::max throughout

Otherwise including <string> or some other C++ header is broken.
E.g.:

  In file included from /opt/gcc/include/c++/7.0.0/bits/char_traits.h:39:0,
		   from /opt/gcc/include/c++/7.0.0/string:40,
		   from /home/pedro/gdb/mygit/cxx-convertion/src/gdb/infrun.c:68:
  /opt/gcc/include/c++/7.0.0/bits/stl_algobase.h:243:56: error: macro "min" passed 3 arguments, but takes just 2
       min(const _Tp& __a, const _Tp& __b, _Compare __comp)
							  ^
  /opt/gcc/include/c++/7.0.0/bits/stl_algobase.h:265:56: error: macro "max" passed 3 arguments, but takes just 2
       max(const _Tp& __a, const _Tp& __b, _Compare __comp)
							  ^
  In file included from .../src/gdb/infrun.c:21:0:

To the best of my grepping abilities, I believe I adjusted all min/max
calls.

gdb/ChangeLog:
2016-09-16  Pedro Alves  <palves@redhat.com>

	* defs.h (min, max): Delete.
	* aarch64-tdep.c: Include <algorithm> and use std::min and
	std::max throughout.
	* aarch64-tdep.c: Likewise.
	* alpha-tdep.c: Likewise.
	* amd64-tdep.c: Likewise.
	* amd64-windows-tdep.c: Likewise.
	* arm-tdep.c: Likewise.
	* avr-tdep.c: Likewise.
	* breakpoint.c: Likewise.
	* btrace.c: Likewise.
	* ctf.c: Likewise.
	* disasm.c: Likewise.
	* doublest.c: Likewise.
	* dwarf2loc.c: Likewise.
	* dwarf2read.c: Likewise.
	* environ.c: Likewise.
	* exec.c: Likewise.
	* f-exp.y: Likewise.
	* findcmd.c: Likewise.
	* ft32-tdep.c: Likewise.
	* gcore.c: Likewise.
	* hppa-tdep.c: Likewise.
	* i386-darwin-tdep.c: Likewise.
	* i386-tdep.c: Likewise.
	* linux-thread-db.c: Likewise.
	* lm32-tdep.c: Likewise.
	* m32r-tdep.c: Likewise.
	* m88k-tdep.c: Likewise.
	* memrange.c: Likewise.
	* minidebug.c: Likewise.
	* mips-tdep.c: Likewise.
	* moxie-tdep.c: Likewise.
	* nds32-tdep.c: Likewise.
	* nios2-tdep.c: Likewise.
	* nto-procfs.c: Likewise.
	* parse.c: Likewise.
	* ppc-sysv-tdep.c: Likewise.
	* probe.c: Likewise.
	* record-btrace.c: Likewise.
	* remote.c: Likewise.
	* rs6000-tdep.c: Likewise.
	* rx-tdep.c: Likewise.
	* s390-linux-nat.c: Likewise.
	* s390-linux-tdep.c: Likewise.
	* ser-tcp.c: Likewise.
	* sh-tdep.c: Likewise.
	* sh64-tdep.c: Likewise.
	* source.c: Likewise.
	* sparc-tdep.c: Likewise.
	* symfile.c: Likewise.
	* target-memory.c: Likewise.
	* target.c: Likewise.
	* tic6x-tdep.c: Likewise.
	* tilegx-tdep.c: Likewise.
	* tracefile-tfile.c: Likewise.
	* tracepoint.c: Likewise.
	* valprint.c: Likewise.
	* value.c: Likewise.
	* xtensa-tdep.c: Likewise.
	* cli/cli-cmds.c: Likewise.
	* compile/compile-object-load.c: Likewise.