toolchain/52725: acpica build fails

[martin%NetBSD.org@localhost]

>Number:         52725
>Category:       toolchain
>Synopsis:       acpica build fails
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Nov 13 11:10:00 +0000 2017
>Originator:     Martin Husemann
>Release:        NetBSD 8.99.6
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD seven-days-to-the-wolves.aprisoft.de 8.99.6 NetBSD 8.99.6 (GENERIC) #173: Mon Nov 13 09:47:38 CET 2017 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:

Depending on phase of moon or exact timestamps after a cvs update, the
acpica build sometimes fails:

/work/src/sys/external/bsd/acpica/dist/compiler/dtexpress.c:45:24: fatal error: 
dtparser.y.h: No such file or directory
compilation terminated.
nbmkdep: compile failed.
*** [dtexpress.d] Error code 1


>How-To-Repeat:

Remove objdir of acpica, cvs up, run build.sh -u.
Probably works by pure luck on a complete new checkout.

>Fix:
touch some magic files after cvs up?