Regression in 5.2.2, i.e., the OP's compilation bug is back: ...
CC [M] /var/lib/dkms/virtualbox/5.2.2/build/vboxpci/linux/VBoxPci-linux.o
CC [M] /var/lib/dkms/virtualbox/5.2.2/build/vboxpci/VBoxPci.o
CC [M] /var/lib/dkms/virtualbox/5.2.2/build/vboxpci/SUPR0IdcClient.o
CC [M] /var/lib/dkms/virtualbox/5.2.2/build/vboxpci/SUPR0IdcClientComponent.o
CC [M] /var/lib/dkms/virtualbox/5.2.2/build/vboxpci/linux/SUPR0IdcClient-linux.o
/var/lib/dkms/virtualbox/5.2.2/build/vboxpci/linux/VBoxPci-linux.c:44:10: fatal error: VBoxPciInternal.h: No such file or directory
#include "VBoxPciInternal.h"
^~~~~~~~~~~~~~~~~~~
compilation terminated.
scripts/Makefile.build:319: recipe for target '/var/lib/dkms/virtualbox/5.2.2/build/vboxpci/linux/VBoxPci-linux.o' failed
make[2]: *** [/var/lib/dkms/virtualbox/5.2.2/build/vboxpci/linux/VBoxPci-linux.o] Error 1
make[2]: *** Waiting for unfinished jobs....
scripts/Makefile.build:578: recipe for target '/var/lib/dkms/virtualbox/5.2.2/build/vboxpci' failed
make[1]: *** [/var/lib/dkms/virtualbox/5.2.2/build/vboxpci] Error 2
Makefile:1520: recipe for target '_module_/var/lib/dkms/virtualbox/5.2.2/build' failed
make: *** [_module_/var/lib/dkms/virtualbox/5.2.2/build] Error 2
make: Leaving directory '/usr/src/linux-headers-4.14.1-towo.2-siduction-amd64'
# uname -a
Linux bla 4.14.1-towo.2-siduction-amd64 #1 SMP PREEMPT siduction 4.14-4 (2017-11-22) x86_64 GNU/Linux
# dpkg -l virtualbox*|grep ii
ii virtualbox 5.2.2-dfsg-1 amd64 x86 virtualization solution - base binaries
ii virtualbox-dkms 5.2.2-dfsg-1 all x86 virtualization solution - kernel module sources for dkms
ii virtualbox-ext-pack 5.2.2-2 all extra capabilities for VirtualBox, downloader.
ii virtualbox-qt 5.2.2-dfsg-1 amd64 x86 virtualization solution - Qt based user interface