[BUGFIX] Do not pass extTarget by reference

As config.extTarget might not be set, passing
it by reference results in the string "< config.extTarget"
being passed instead - which will not evaluate to empty
therefor breaking the fallback chain.

Resolves: #89994
Releases: master, 9.5
Change-Id: Ice368e3d139309b32fb886538ef69437f62b3cc7
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62752


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>

typo3/sysext/fluid_styled_content/Configuration/TypoScript/Helper/ParseFunc.typoscript

@@ -22,7 +22,9 @@ lib.parseFunc {
                 target.ifEmpty.data = parameters:target
                 # the target attribute takes precedence over the constant (styles.content.links.extTarget)
                 # which takes precedence over config.extTarget
-                extTarget.ifEmpty =< config.extTarget
+                # do not pass extTarget as reference, as it might not be set resulting in the string being
+                # written to the target attribute
+                extTarget.ifEmpty < config.extTarget
                 extTarget.ifEmpty.override = {$styles.content.links.extTarget}
                 extTarget.override.data = parameters:target
             }