Bug#913946: llvm*7-dbgsym still missing

[Rebecca N. Palmer]

Control: reopen -1
Control: tags -1 patch
(though I haven't tried it)

This doesn't work on the buildds: still no -dbgsym packages, and the 
errors now say

PATH=/<<BUILDDIR>>/llvm-toolchain-7-7.0.1~+rc2/:$PATH 
LD_LIBRARY_PATH=/<<BUILDDIR>>/llvm-toolchain-7-7.0.1~+rc2/debian/tmp//usr/lib/llvm-7/lib/ 
dh_strip -p libclang1-7 --dbgsym-migration='libclang1-7-dbg (<< 
1:7~svn327768-1~)'
ERROR: ld.so: object 'libfakeroot-sysv.so' from LD_PRELOAD cannot be 
preloaded (cannot open shared object file): ignored.

This suggests that your setting of LD_LIBRARY_PATH is overwriting the 
existing one, breaking fakeroot (a known issue - 
https://sources.debian.org/src/fakeroot/1.23-1/doc/fakeroot.1/#L191 ): 
try LD_LIBRARY_PATH=$$LD_LIBRARY_PATH:[build dir]

(Also, does this give _working_ -dbgsym packages, or just take us back 
to #914021?)