Rather than testing that a constant expression produces so many
instructions, test that a variety of of such expressions produce the
same number of instructions. This will make future changes in the
compiler less likely to break this test.
This allows one to force the use of jq's builtin copy of Oniguruma
(builtin as a git submodule).
We still need to fix make dist to include that copy of Oniguruma.
Configure should still allow use of prebuilt onigurumas (whether
system-installed or in a special prefix). If these are not found, and
configure was not called with `--without-oniguruma`, then use the vendored
oniguruma module. If configure was called with `--without-oniguruma`, then we
do not build regex functionality into jq.
Now that #1313 is fixed, |= no longer outputs null when the RHS update
expression outputs empty.
When a user wants to keep the current value of the LHS they would have
the RHS update expression output `.`, so having `empty` achieve the same
thing would be redundant. The obvious thing to do is to delete the LHS
when the RHS update outputs `empty` (i.e., doesn't output any values).
It's reasonable to think that existing programs won't be broken by this
change, because reduce and |= not handling empty well is clearly a bug.
(Though it's possible that some programs were using empty to quickly
terminate reduce or |=, it's not likely. They should use label/break
instead.)
Prior to this change |= would use the _last_ value output by the RHS
update expression. With this change |= will use the _first_ value
instead. This change _is_ a minor backwards-incompatible change. It
may or may not be acceptable; we'll see. It is a useful change in that
it makes |= faster when the update expression produces multiple values.
first(g) was extracting two values, which, if g is slow, made first(g)
slow. And if the second extraction were to throw an error, then
first(g) would throw that error, which is clearly not the right thing to
do. Besides that, first(g) was allocating garbage, which it no longer
does.
