Fix #1443 macOS: regression_test.sh: mktemp: illegal option (#1444)

The macOS version of mktemp does not recognize the --suffix option.
Using pure -d should work since, it seems [1], macOS 10.11 however.

So to make the script work on macOS, stop using the --suffix option.

The downside is of course that the temporary dir will have an anonymous
name, but I see no risk of confusion given how short-lived the usage of
the dir is, and given the context it is used.

[1] https://unix.stackexchange.com/questions/30091/fix-or-alternative-for-mktemp-in-os-x

CHANGELOG.md

@@ -6,6 +6,7 @@
 ## Bugfixes
 
 - only print themes hint in interactive mode (`bat --list-themes`), see #1439 (@rsteube)
+- Make ./tests/syntax-tests/regression_test.sh work on recent versions of macOS, see #1443 (@Enselic)
 
 ## Other
 

tests/syntax-tests/regression_test.sh

@@ -4,7 +4,7 @@ set -eou pipefail
 
 script_directory="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
 
-output_directory=$(mktemp -d --suffix=.bat-syntax-regression-test)
+output_directory=$(mktemp -d)
 
 "$script_directory"/create_highlighted_versions.py --output="$output_directory"