zile: fix posix.euidaccess usage.

* lib/zile/file.lua (checkwriteable): Allow for euidaccess to be
imported from the posix table, or from the new posix.sys table.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
specs: fix posix.spawn usage.

* lib/zemacs/specs/spec_helper.lua (edit): Allow for spawn to be
imported from the posix table, or from the new posix.sys table.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
maint: add a waffle.io badge to README.md.

* README.md: Add a waffle.io badge.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
zile: zile.Array module moved to std.array.

* lib/zile/Array.lua: Remove.
* lib/zile/zile.mk (dist_pkgdata_DATA): Remove
lib/zile/Array.lua.
* build-aux/config.ld.in (file): Remove lib/zile/Array.lua.
* local.mk (dist_classes_DATA): Remove
doc/classes/zile.Array.html.
* lib/zile/syntax.lua (Array): Import from new std.array, not
removed zile.Array.
* lib/zile/lib.lua (concat, argcheck, argerror, argscheck):
Remove. Also moved to stdlib, and not used by any other Zile
code.
* bin/zemacs, bin/zz: Since we use std.strict, and (via
std.array) std.debug, we must define _DEBUG before first
reference in std.debug_init.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
refactor: eliminate remaining zile.lib stack uses.

Now that stdlib-41 has sufficiently full featured std.array
objects, we can remove the last hold-out uses of impromptu
zile.lib stacks.
* lib/zile/lib.lua (stack, metatable): Remove.
* lib/zile/syntax.lua (metatable.push_op, state.caps, state.pats):
Use std.array instead of zile.lib.stack.
Adjust all clients.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
syntax: avoid spurious zeros for uncolored subexpression matches.

Save an attribute push and pop on most lines.
* lib/zile/syntax.lua (parse): If there is no color attribute
specified in a subexpression match, simply ignore it.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>