Closes Homebrew/homebrew#23931.

The cc wrapper's make_fuss is only enabled when HOMEBREW_CCCFG contains
'O', which is set by the make wrapper. This means it is disable when
running configure scripts. However, this does not include configure
scripts invoked by make, which inherit the value of HOMEBREW_CCCFG from
the make process. make_fuss will be enabled for these scripts, cause
breakage.

Configure scripts generated by autoconf 2.56 (November 2002) or later
export DUALCASE into the environment of subprocesses. This variable is
only used by the MKS shell, so we can use it as a heuristic to determine
if we are running as a subprocess of a configure script.

Fixes Homebrew/homebrew#23936.

In 6e3a585607116d06f47aac2ff5a649f2898216f0 ("Improve superenv
add/remove message."), more debugging information was added to the
"make_fuss" output generated by the superenv compiler
wrapper.

This resulted in some breakage in configure scripts that inspect stderr,
so in e1bd9b9e980c433878e60833f09964b8ca996657 ("Don't use stderr for
make_fuss output."), the output was moved to stdout. This only appeared
to solve the problem, since stdout is buffered but stderr is not.

Later, in fb749e47509b77b5bd89e7b14f0a1097d4af7f40, Homebrew started
generating logs even in verbose mode. This had the side effect of moving
stdout/stderr from a TTY to a pipe, and thus stdout was no longer
line-buffered.

Since it was not line-buffered, and Ruby's internal buffers were not
flushed, the debug output was being lost. This was addressed in
2d5724af8613c820b8c14f4171fe1de6a17f10c3 ("cc: ensure wrapper output is
always flushed").

This caused stdout to be flushed during configure, which resurfaced the
original bug that prompted e1bd9b9e980c433878e60833f09964b8ca996657.
This was fixed by disabling the debug output during configure, in
f1779837a46a58520560fba3850a0e2992284d0a.

Since the original bug has been addressed in a more robust way, we can
move the debug output back to stderr.

Fixes Homebrew/homebrew#23923.

These options are deprecated in favor of --cc=<compiler>, so there is no
need to continue advertising their existence.

Now that ErrorDuringExecution is only raised in one place, we can just
raise the BuildError directly instead.

The default mode is intended to display recursive dependencies, with the
`--1` flag to display only one level.

* In certain cases, a C++ software may result in linking to a different
  and incompatible C++ standard library than its dependencies and still
  works fine because it is by design. Examples include GCC, which will
  bootstrap itself and self-host after finish.

* Add a cxxstdlib_check method to formula to request changing the C++
  standard library checking. Currently using "cxxstdlib_check :skip"
  will let a formula skip such checking. This should only be used on
  rare occasions and be very careful.

Closes Homebrew/homebrew#23687.

* This is consistent with superenv.

Fixes Homebrew/homebrew#23881.

Fixes Homebrew/homebrew#23885.

This is broken and nobody noticed, so remove it.

Closes Homebrew/homebrew#23878.

Closes Homebrew/homebrew#23874.

Fixes Homebrew/homebrew#23837.
Fixes Homebrew/homebrew#23866.

* When Homebrew developer mode is enabled, if a bottle is not found to
  be relocatable attempt to explain why
* Print out paths of each file that still contains the string search for
* If the string searched for was found in an executable, check to see
  if `otool` can explain the string's appearance
* If otool can't explain, see if `strings` can explain

Closes Homebrew/homebrew#23824.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Fixes Homebrew/homebrew#23764.

Closes Homebrew/homebrew#23654.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Fixes Homebrew/homebrew#23835.

Closes Homebrew/homebrew#23796.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>

I've given up on this; too many edge cases.
If someone else wants to pick it up then send me a message and I'll walk
you through the approach.

We hate it and we should tell people why.
Next step may be blocking it altogether.

When a formula is removed from core and installed let's tap it so users
can get updates without caring which tap we want to put things in.

This should allow us to migrate a lot of things to taps.

Closes Homebrew/homebrew#23760.