Add FreeBSD binaries, bump up version to v1.29.1

Bump up version for v1.29.0 release

Bump up version number; forgot to do this for release, so go to v1.28.1

Bump up minimum supported Go version to 1.18, and test on 1.23

Bump up version number for v1.27.0 release

Bump up version number for v1.26.0 release

Build with PGO - it's more than 5% faster

We can probably get a more realistic PGO profile than just running the
microbenchmarks, but it'll do.

goawk=go1.21.0 with PGO
orig =go1.21.0 without PGO

Test                         |    goawk |     orig |      awk
---------------------------- | -------- | -------- | --------
tt.01 (print)                |     3.02 |     2.76 |     1.00
tt.02 (print NR NF)          |     2.07 |     1.95 |     1.00
tt.02a (print length)        |     1.85 |     1.80 |     1.00
tt.03 (sum length)           |     1.53 |     1.47 |     1.00
tt.03a (sum field)           |     1.47 |     1.44 |     1.00
tt.04 (printf fields)        |     1.36 |     1.21 |     1.00
tt.05 (concat fields)        |     1.54 |     1.48 |     1.00
tt.06 (count lengths)        |     1.64 |     1.55 |     1.00
tt.07 (even fields)          |     1.49 |     1.43 |     1.00
tt.08 (even lengths)         |     2.54 |     2.60 |     1.00
tt.08z (regex simple)        |     3.73 |     3.71 |     1.00
tt.09 (regex starts with)    |     2.87 |     2.83 |     1.00
tt.10 (regex ends with)      |     0.47 |     0.45 |     1.00
tt.10a (regex ends with var) |     0.45 |     0.44 |     1.00
tt.11 (substr)               |     3.35 |     3.16 |     1.00
tt.12 (update fields)        |     1.53 |     1.51 |     1.00
tt.13 (array ops)            |     4.84 |     4.28 |     1.00
tt.13a (array printf)        |     3.03 |     2.83 |     1.00
tt.14 (function call)        |     1.73 |     1.50 |     1.00
tt.15 (format lines)         |     1.00 |     0.97 |     1.00
tt.16 (count words)          |     1.92 |     1.77 |     1.00
tt.big (complex program)     |     2.29 |     2.17 |     1.00
tt.x1 (mandelbrot)           |     2.68 |     2.67 |     1.00
tt.x2 (sum loop)             |     2.41 |     2.19 |     1.00
---------------------------- | -------- | -------- | --------
**Geo mean**                 | **1.86** | **1.76** | **1.00**

Bump up version for release

Bump up patch version for v1.23.3 release

Fix "undefined function" error with mutually-recursive functions (#184)

Fix "undefined function" error with mutually-recursive functions

When the AWK code defines mutually-recursive functions, the topological
sort can't help us. So define all funcInfos in the initial call-graph
pass before doing any resolver passes. This avoids the "undefined
function" error in those cases.

Add a minimal test for this, and also add a test of parsing/using the
gron.awk code, as it's a nice, fairly complex test case.

Fixes #183. Thanks @xonixx for the bug report!