formula_installer: default_formula using build.

Use the build options instead of whether the requirement is optional to
work out if it is needed. This handles the case of an optional
requirement becoming needed because it's a dependency for another
formula.

Closes #31476.
nvm 0.13.1

Closes #31510.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
vim: fixes for issue #31337

 - add default perl support to match MacVim

Closes #31367.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
MacVim: fixes for issue #31337

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
formula_installer: check for recommended/optional.

build.without? seemingly always returns true for requirements that are
neither recommended nor optional so check these before deciding not to
install a default formula.

Closes #31511.
libav: remove unnecessary configure options
libav: enable VDA code
libav: update 10.3 bottle.

Closes #31490.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
Allow build to be set externally
Replace the build object rather than mutate it
Deep copies of the build object are no longer needed
mono: Don't clean mono's runtime directories.

xbuild requires the various .exe files in the runtime directories to
be executable.

Closes #31457.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
mono: update 3.4.0_1 bottle.
nexus 2.9.0-04

Closes #31520.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
fsharp 3.1.1.25

Closes #30808.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
fsharp: update 3.1.1.25 bottle.
fsharp: remove unnecessary setup
hevea 2.16

Closes #31441.
hevea: update 2.14 bottle.
mongodb 2.6.4

Closes #31517.

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