Package: libdebhelper-perl Version: 13.1 Severity: normal Apparently, dh7 fails to tell qmake the location of the source directory when attempting an out-of-tree build:
[…] dpkg-source: info: building polyphone in polyphone_2.2.0+dfsg0-1.dsc debian/rules binary dh binary --sourcedir=sources -B dh_update_autotools_config -O--sourcedir=sources -O-B dh_autoreconf -O--sourcedir=sources -O-B dh_auto_configure -O--sourcedir=sources -O-B install -d /tmp/buildd/polyphone-2.2.0\+dfsg0/debian/.debhelper/generated/_source/home /tmp/buildd/polyphone-2.2.0\+dfsg0/debian/.debhelper/generated/_source/xdg-runtime-dir install -d obj-x86_64-linux-gnu cd obj-x86_64-linux-gnu && qmake -makefile "QMAKE_CFLAGS_RELEASE=-g -O2 -fdebug-prefix-map=/tmp/buildd/polyphone-2.2.0+dfsg0=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 " "QMAKE_CFLAGS_DEBUG=-g -O2 -fdebug-prefix-map=/tmp/buildd/polyphone-2.2.0+dfsg0=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 " "QMAKE_CXXFLAGS_RELEASE=-g -O2 -fdebug-prefix-map=/tmp/buildd/polyphone-2.2.0+dfsg0=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 " "QMAKE_CXXFLAGS_DEBUG=-g -O2 -fdebug-prefix-map=/tmp/buildd/polyphone-2.2.0+dfsg0=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 " "QMAKE_LFLAGS_RELEASE=-Wl,-z,relro -Wl,-z,now -Wl,--as-needed" "QMAKE_LFLAGS_DEBUG=-Wl,-z,relro -Wl,-z,now -Wl,--as-needed" QMAKE_STRIP=: PREFIX=/usr Usage: /usr/lib/qt5/bin/qmake [mode] [options] [files] QMake has two modes, one mode for generating project files based on […] The qmake invocation syntax error message is somewhat misleading, but looking at the invocation command line it becomes somewhat clearer. -- System Information: Debian Release: bullseye/sid APT prefers unstable-debug APT policy: (500, 'unstable-debug'), (500, 'oldstable-updates'), (500, 'buildd-unstable'), (500, 'unstable'), (500, 'oldstable'), (1, 'experimental-debug'), (1, 'experimental') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 5.6.0-2-amd64 (SMP w/2 CPU cores) Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE=C.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/lksh Init: sysvinit (via /sbin/init) Versions of packages libdebhelper-perl depends on: ii perl 5.30.3-4 libdebhelper-perl recommends no packages. libdebhelper-perl suggests no packages. -- no debconf information