[FEATURE REQUEST] makeDynCall macro for pre or post js files

[marcusx2]

Currently the new makeDynCall struct doesn't work on pre or post js files. It would be incredibly useful if it did. If a use case is needed, this is for Unity so it can be used on .jspre files. @juj can probably elaborate more.

[Zarbuz]

Up ! This would very usefull for Unity

[sbc100]

As of #21227 you can now add #preprocess to the start of you pre/post JS files which will cause them to be processed and you can then use all the macros such as makeDynCall