While awk is POSIX, perl isn't pre-installed on all *nix flavors.
This commit eliminates the mandatory dependency on perl by using awk
when perl is not available.
Related: #3295, #3309, #3310.
Test suite passed:
* `make error` all test sections 'PASS'
* `make docker-test` 215 runs, 1884 assertions, 0 failures, 0 errors, 0 skips.
Manually tested in the following environments:
* Linux amd64 with bash 3.2, 4.4, 5.2; gawk -P, one true awk, mawk, busybox awk.
* macOS Catalina, bash 3.2, macOS awk 20070501.
**Performance comparison:**
Mawk turned out the fastest, then perl.
One true awk's implementation should be the closest to macOS awk.
Test data: 230 KB history, 15102 entries, including multi-line and duplicates.
Linux, bash 4.4. Times in milliseconds.
| Command | Mean | Min | Max | Relative |
| :--- | ---: | ---: | ---: | -------: |
| `mawk 1.3.4` | 22.9 | 22.3 | 25.6 | **1.00** |
| `perl 5.26.1` | 34.3 | 33.6 | 35.1 | 1.49 |
| `one true awk 20221215` | 41.9 | 40.6 | 46.3 | 1.83 |
| `gawk 5.1.0` | 46.1 | 44.4 | 50.3 | 2.01 |
| `busybox awk 1.27.0` | 64.8 | 63.2 | 70.0 | 2.82 |
**Other Notes**
A bug affects bash, which fails restoring a saved multi-line history entry as a single entry. Bug fixed in version 5.0.[^1]
While developing this PR I discovered two unsubmitted issues affecting the current perl script. The output stream ends with `$'\n\0000'` instead of `$'\0000'`. Because of this, the script does not deduplicate a duplicated entry located at the end of the history list; therefore fzf displays two identical (not necessarily adjacent) entries. A minor point about the first issue is that the top fzf entry ends with a dangling line feed symbol, which is visible in the terminal.
[^1]: https://github.com/bminor/bash/blob/ec8113b9861375e4e17b3307372569d429dec814/CHANGES#L1511
To enable: `shopt -s cmdhist lithist; HISTTIMEFORMAT='%F %T '`.
