GHC build regression ("HSghc-prim-0.5.3.p_o: copyFile: does not exist")

Ben asked me to file this here:

Some time between 8.7.20181015+git.1.2e1df7c1 and 8.7.20181210+git.1.4773b430 the GHC build process as orchestrated by the automated PPA Debian package builds started failing with

/usr/bin/install -c -m 755 -d  "/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp/opt/ghc/head/lib/ghc-8.7.20181210/rts"
for i in  rts/dist/build/libHSrts.a rts/dist/build/libHSrts-ghc8.7.20181210.so rts/dist/build/libHSrts_p.a rts/dist/build/libHSrts_l.a rts/dist/build/libHSrts_debug.a rts/dist/build/libHSrts_thr.a rts/dist/build/libHSrts_thr_debug.a rts/dist/build/libHSrts_thr_l.a rts/dist/build/libHSrts_thr_p.a rts/dist/build/libHSrts_debug-ghc8.7.20181210.so rts/dist/build/libHSrts_thr-ghc8.7.20181210.so rts/dist/build/libHSrts_thr_debug-ghc8.7.20181210.so rts/dist/build/libHSrts_l-ghc8.7.20181210.so rts/dist/build/libHSrts_thr_l-ghc8.7.20181210.so rts/dist/build/libHSrts_thr_debug_p.a rts/dist/build/libHSrts_debug_p.a rts/dist/build/libffi.so rts/dist/build/libffi.so.7 rts/dist/build/libffi.so.7.1.0 rts/dist/build/libCffi.a rts/dist/build/libCffi_p.a rts/dist/build/libCffi_l.a rts/dist/build/libCffi_debug.a rts/dist/build/libCffi_thr.a rts/dist/build/libCffi_thr_debug.a rts/dist/build/libCffi_thr_l.a rts/dist/build/libCffi_thr_p.a rts/dist/build/libCffi_thr_debug_p.a rts/dist/build/libCffi_debug_p.a; do case $i in *.a) /usr/bin/install -c -m 644  $i  "/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp/opt/ghc/head/lib/ghc-8.7.20181210/rts"; true  "/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp/opt/ghc/head/lib/ghc-8.7.20181210/rts"/`basename $i` ;; *.dll) /usr/bin/install -c -m 755  $i  "/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp/opt/ghc/head/lib/ghc-8.7.20181210/rts" ; strip  "/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp/opt/ghc/head/lib/ghc-8.7.20181210/rts"/`basename $i` ;; *.so) /usr/bin/install -c -m 755  $i  "/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp/opt/ghc/head/lib/ghc-8.7.20181210/rts" ;; *.dylib) /usr/bin/install -c -m 755  $i  "/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp/opt/ghc/head/lib/ghc-8.7.20181210/rts";; *) /usr/bin/install -c -m 644  $i  "/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp/opt/ghc/head/lib/ghc-8.7.20181210/rts"; esac; done
"inplace/bin/ghc-cabal" copy libraries/ghc-prim dist-install "strip" '/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp' '/opt/ghc/head' '/opt/ghc/head/lib/ghc-8.7.20181210' '/opt/ghc/head/share/doc/ghc-8.7.20181210/html/libraries' 'v dyn p'  
Installing library in /<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp/opt/ghc/head/lib/ghc-8.7.20181210/ghc-prim-0.5.3
dist-install/build/HSghc-prim-0.5.3.p_o: copyFile: does not exist (No such file or directory)
make[2]: *** [install_packages] Error 1
make[1]: *** [install] Error 2
make[1]: Leaving directory `/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43'
dh_auto_install: make -j4 install DESTDIR=/<<BUILDDIR>>/ghc-head-8.7.20181210+git.1.4773b43/debian/tmp AM_UPDATE_INFO_DIR=no returned exit code 2

Full logs available at https://launchpadlibrarian.net/401081604/buildlog_ubuntu-trusty-amd64.ghc-head_8.7.20181210+git.1.4773b43-9~14.04_BUILDING.txt.gz

Trac metadata

Trac field	Value
Version	8.7
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Build System (make)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture