https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90770
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- The problem is that the src/debug directory exists, but has no Makefile. The recipe for the stamp-debug target only checks whether the directory exists, so does not create any Makefiles: if test ! -d /home/eus/buildzone/gcc-9-build/x86_64-linux-gnu/libstdc++-v3/src/debug; then \ mkdir -p /home/eus/buildzone/gcc-9-build/x86_64-linux-gnu/libstdc++-v3/src/debug; \ for d in c++98 c++11 c++17 filesystem; do mkdir -p /home/eus/buildzone/gcc-9-build/x86_64-linux-gnu/libstdc++-v3/src/debug/$d; done; \ (cd /home/eus/buildzone/gcc-9-build/x86_64-linux-gnu/libstdc++-v3/src/debug; \ sed -e 's/top_builddir = \.\./top_builddir = ..\/../' \ -e 's/top_build_prefix = \.\./top_build_prefix = ..\/../' \ -e 's/srcdir = \.\./srcdir = ..\/../' \ -e 's/VPATH = \.\./VPATH = ..\/../' \ -e 's/glibcxx_basedir = \.\./glibcxx_basedir = ..\/../' \ -e 's/MKDIR_P = \.\./MKDIR_P = ..\/../' \ < ../Makefile > Makefile ; \ for d in . c++98 c++11 c++17 filesystem; do \ sed -e 's/top_builddir = \.\./top_builddir = ..\/../' \ -e 's/top_build_prefix = \.\./top_build_prefix = ..\/../' \ -e 's/srcdir = \.\./srcdir = ..\/../' \ -e 's/VPATH = \.\./VPATH = ..\/../' \ -e 's/glibcxx_basedir = \.\./glibcxx_basedir = ..\/../' \ -e 's/MKDIR_P = \.\./MKDIR_P = ..\/../' \ < ../$d/Makefile > $d/Makefile ; \ done) ; \ fi; \ echo `date` > stamp-debug; I'm not yet sure where all the makefiles have gone. If the 'clean-local' target had been used it should have removed the directory.