Compilation errors are not recognized, long paths

The download manager 2.0.6.2 is buggy (?) and does not always detect when the installation has failed. 
In my case, among other things, the ".bpl" files were not created, which I only found out after a long research. Extract from the log file:

error MSB6003: The specified executable file of the task "dcc" could not be executed. 
The file name or extension is too long [C:\Users\lrcu\Documents\tmssoftware\TMS FNC UI Pack\FMXTMSFNCUIPackPkgDXE12.dproj].

This is partly because I have adopted the default file path and TMS is generally relatively generous in its naming.
 -> C:\Users\lrcu\Documents\tmssoftware\TMS FNC UI Pack\FMXTMSFNCUIPackPkgDXE12.dproj
 versus 
 -> C:\Komp103\TMS FNC UI Pack\FMXTMSFNCUIPackPkgDXE12.dproj

What also surprises me is that the libraries are listed by other products, so the limit of 32k is easily exceeded.

Extract from the log file "TMS FNC Core_2.2.0.2.log":
_PasCoreCompile:
  C:\Program Files (x86)\Embarcadero\Studio\20.0\bin\dcc32.exe -$D0 -$L- -$Y- --no-config -B -Q -Z -TX.bpl -AGenerics.Collections=System.Generics.Collections;Generics.Defaults=System.Generics.Defaults;WinTypes=Winapi.Windows;WinProcs=Winapi.Windows;DbiTypes=BDE;DbiProcs=BDE;DbiErrs=BDE -DRELEASE -E.\Win32\Release -I"c:\program files (x86)\embarcadero\studio\20.0\lib\Win32\release\DE";(x86)\embarcadero\studio\20.0\lib\Win32\release";
C:\Users\lrcu\Documents\Embarcadero\Studio\20.0\Imports;
..
..
"C:\Users\lrcu\Documents\tmssoftware\TMS VCL UI PackDelphi103Rio\Win32\Release";
"C:\Users\lrcu\Documents\tmssoftware\TMS FMX UI PackDelphi103Rio\Win32\Release";
"C:\Users\lrcu\Documents\tmssoftware\TMS VCL Instrumentation Workshop";
"C:\Users\lrcu\Documents\tmssoftware\TMS VCL Instrumentation Workshop\Delphi103Rio\Win32\Release";
...
...
C:\Komp\jvcl\jvcl\lib\D26\win32;
"C:\Users\lrcu\Documents\tmssoftware\TMS FMX UI Pack";
...
...
"C:\Users\lrcu\Documents\tmssoftware\TMS WEB Core RSXE12";
...
...
"C:\Users\lrcu\Documents\tmssoftware\TMS FNC UI Pack\xlsAdapter";
...
...
C:\Program Files (x86)\Embarcadero\Studio\20.0\Bin\CodeGear.Delphi.Targets(402,5): warning MSB6002: Die Befehlszeile fr die DCC-Aufgabe ist zu lang. Bei Befehlszeilen mit mehr als 32000 Zeichen treten h„ufig Fehler auf. Versuchen Sie, die Befehlszeile zu krzen, indem Sie den Aufruf von DCC in mehrere Aufrufe mit weniger Parametern pro Aufruf unterteilen. [C:\Users\lrcu\Documents\tmssoftware\TMS FNC UI Pack\FMXTMSFNCUIPackPkgDXE12.dproj]
C:\Program Files (x86)\Embarcadero\Studio\20.0\Bin\CodeGear.Delphi.Targets(402,5): error MSB6003: Die angegebene ausfhrbare Datei der Aufgabe "dcc" konnte nicht ausgefhrt werden. Der Dateiname oder die Erweiterung ist zu lang [C:\Users\lrcu\Documents\tmssoftware\TMS FNC UI Pack\FMXTMSFNCUIPackPkgDXE12.dproj]
Die Erstellung des Projekts "C:\Users\lrcu\Documents\tmssoftware\TMS FNC UI Pack\FMXTMSFNCUIPackPkgDXE12.dproj" ist abgeschlossen, Build Ziel(e) -- FEHLER.

The download manager task is to download and launch the installer, which it does.
The installer task is to compile the packages from the command line for install in the IDE, which it does. Here the command line compiler fails to compile the packages and this normally should be reported by the installer at the end of the compilation step telling that compilation of the packages failed.
There can be various reasons for failure of compiling from the command-line, an excessive library path length is one of them as it is a limitation of MSBUILD that handles the command-line compilation that it can only deal with a command-line of 32K characters.
I would advise to sanitize your library path and remove the unused paths to get the total size below 32K or to compile the packages from the Delphi IDE (as this does not have the 32K limit)

In my case, most libraries are from TMS (all access) and there are no outdated paths. 

As suggested by the Download Manager, most users will probably use the default path and will reach the system boundaries very quickly thanks to the name length. 
Unfortunately the installer doesn't notice anything and you only notice it when you start the IDE.

In my case I finally uninstalled all TMS components and saved them at another Location.

from:
C:\Users\lrcu\Documents\tmssoftware\TMS FNC UI Pack\

to (for example) 
C:\Komp103\TMS FNC UI Pack\ (-25 characters)

This is the only way I can finally install and use the required TMS components. 

Is it not possible to reduce the name length in general?
e.g. from "tmssoftware\TMS FNC UI Pack"  to "TMS\FNC UI Pack" (-12 characters)

Question:
Why are all paths always included when compiling?
Is this really necessary or is it predefined?
Can the installer not set up an environment variable?

All paths are used because that is the same way as it would happen from the IDE.
When we would only pick one path, possible there is an install error (for example previous version was not uninstalled) and it will appears as if everything is OK while it isn't.

We've considered the use of an environment variable but it is an extra complexity, something the user could fiddle with behind the back of the installer, restrictions to set this environment variable from our installer, etc...  so it is not the magical solution that would ensure it will work in all cases.