Build fixes: PDFfolder.png, SDKROOT, formatting.

[mckenfra]

This PDF printer driver works great, thanks a lot! I've made a few fixes to buildscript.sh, as it was generating the following errors when run on macOS High Sierra (may also affect other OS versions):

ld: warning: text-based stub file /System/Library/Frameworks//appkit.framework/appkit.tbd and library file /System/Library/Frameworks//appkit.framework/appkit are out of sync. Falling back to library file for linking.
ld: warning: text-based stub file /System/Library/Frameworks//Foundation.framework/Foundation.tbd and library file /System/Library/Frameworks//Foundation.framework/Foundation are out of sync. Falling back to library file for linking.
[...repeated many times...]

cp: PDFfolder.png: No such file or directory

Also, the text in the package installation screen looked a bit cramped, so I spaced it out better and formatted the code blocks better too:

Current Version (has some spacing / formatting issues)

New Version (improved spacing & code blocks)

Thanks a lot!

Francis

[rodyager]

Thanks Francis.

This is much appreciated.

Rod