On macOS 10.14 Apple changed the command line tools so that system
headers now need to be manually installed.

Instead of adding one extra install step to the install procedure add a
build tag to allow compilation of delve without the native backend on
macOS. By default (i.e. when using `go get`) this is how delve will be
compiled on macOS, the make script is changed to enable compiling the
native backend if the required dependencies have been installed.

Insure that both configuration still build correctly on Travis CI and
change the documentation to describe how to compile the native backend
and that it isn't normally needed.

Fixes #1359

With this syntax users do not need to type the concrete type of an
interface variable to access its contents. This also sidesteps the
problem where the serialization of a type by go/printer is different
from the one used for debug_info type names.

Updates #1328

Use IsInternal and IsUser of Breakpoint, not duplicate code

We should print something when we exit from continue/next/step/stepout
even if we don't have a source file for the instruction that we are
stopped on.

This is mostly important on macOS where a SIGSEGV will cause 'continue'
to fail with a 'bad access' error (see #852) and the output can be
confusing.

Fixes #1244

Correctly locates the installed executable path for darwin

Go allows converting a single integer value to string, resulting in a
string containing a single unicode rune with the same code as the value
of the integer.
Allow the same conversion to happen.

Fixes #1322

Instead of failing on the first goroutine we can't read save the error
message and keep going.

Fixes a bug reported on the mailing list:
https://groups.google.com/d/msgid/delve-dev/3b3bfaa3-83d5-4676-b974-1fec40e5bf53%40googlegroups.com?utm_medium=email&utm_source=footer

This commit just add an new error when trying to change register
values for core files (output the same infomation).

format `whatis <expression>`

This changes make `dlv` support multifile specifically when dlv `debug`,
`trace` and `test`. Just like `dlv debug a.go b.go`. Corresponding to
`go build a.go b.go`.(a.go and b.go are  belong to `main` package).

Fix #984.

Refactors some code, adds a bunch of docstrings and just generally fixes
a bunch of linter complaints.

An interface with a children that has onlyAddr set to true was not
loaded due to the depth limit having been reached.

We were using our makefile not for the intended purpose of makefiles
but to multiplex a series of small scripts.
We can easily achieve the same result in a more reasonable programming
language and as a bonus we don't need to install a version of make on
windows anymore.
Additionally our test script had become fairly complicated and will
become even more complicated when testing of PIE buildmode is
introduced.
Allows the tests to run on Windows without having to install Mingw
(although we still want it installed so that we can run cgo tests on
Windows).

Fixes building when GOPATH isn't set.

Fixes #759

Explicit build instructions to avoid #1342.

Refactors edit and list so that they use the same code to get the
current location and also both accept a locspec as an argument.

Add a flag to Stackframe that indicates where the stack frame is the
bottom-most frame of the stack. This allows clients to know whether the
stack trace terminated normally or if it was truncated because the
maximum depth was reached.
Add a truncation message to the 'stack' command.

Fncall.go was written with the assumption that the object returned by
proc.Thread.Registers does not change after we call
proc.Thread.SetPC/etc.

This is true for the native backend but not for gdbserial. I had
anticipated this problem and introduced the Save/SavedRegisters
mechanism during the first implementation of fncall.go but that's
insufficient.

Instead:

1. clarify that the object returned by proc.Thread.Registers could
   change when the CPU registers are modified.
2. add a Copy method to Registers that returns a copy of the registers
   that are guaranteed not to change when the CPU registers change.
3. remove the Save/SavedRegisters mechanism.

This solution leaves us the option, in the future, to cache the output
of proc.(Thread).Registers, avoiding a system call every time it's
called.

Implements missing functionality in gdbserial to enable function calls
on OSX.

Normally variables that have a named struct as a type will get a
typedef entry as their type, sometimes however the Go linker will
decide to use the DW_TAG_structure_type entry instead.

For consistency always wrap a struct type into a typedef when we are
creating a new variables (see comment in newVariable for exceptions).

This fixes a bug where it would be impossible to call methods on a
global variable.

Next should work even if one or more instructions in the current
function can not be disassembled.

Explain why we are asking the user to write to a /proc file.

Add new version to CHANGELOG and update internal version.

Thank you @jaym, @slp, @yasushi-saito, @acshekhara1, @benc153,
@yuval-k, @functionary, @psanford @giuscri, @jsoref, @Carpetsmoker,
@PatrickSchuster, @aarzilli, @derekparker, @ramya-rao-a and @dlsniper.

Updated call description to reflect current limitations.

Evaluates var.method expressions into a variable holding the
corresponding method with the receiver variable as a child, in
preparation for extending CallFunction so that it can call methods.

Changes (*Variable).setValue so that it can be used in CallFunction to
set up the argument frame for the function call, adding the ability to:
- nil nillable types
- set strings to the empty string
- copy from one structure to another (including strings and slices)
- convert any interface type to interface{}
- convert pointer shaped types (map, chan, pointers, and structs
  consisting of a single pointer field) to interface{}

This covers all cases where an assignment statement can be evaluated
without allocating memory or calling functions in the target process.

Use the same connect code path whether we started the server (with
debug/exec/test) or we didn't (i.e. the 'connect' subcommand).
This fixes a bug where the init file was ignored with the 'connect'
subcommand and hopefully prevents future divergence between the
behavior of 'connect' and the other subcommands.

Fixes #1301

This patch makes it so inlined functions are returned in the
function
list, and also allows users to set breakpoints on the call site of
inlined functions.

Fixes #1261

Something changed on Travis side that broke TestIssue877. Disable that
test when $TRAVIS is set to true.

Which I miss from gdb-- it's nice to be able to open where you are in
your editor where you're already working on the project you're
debugging.

If we send a process to foreground while the headless instance may get
a SIGTTOU/SIGTTIN, if not ignored this signal will stop the headless.
It's not clear why this only happens the second time we do this but
that's how it is.

Also removes the direct syscall to TIOCSPGRP and lets the go runtime do
it instead.

Fixes #1279