Hi,

Your package uses configure script with bash features not present in
POSIX without explicitly declaring the need to bash shell; this
currently works as configure scripts select bash, but when dash enables
LINENO support, your configure script will start failing:

     ./configure: 6674: test: /usr/bin/curl-config: unexpected operator
     ./configure: 6682: test: x: unexpected operator
     ./configure: 6693: test: x: unexpected operator
     checking for curl (7.74.0) >= 7.15.5... yes
     checking that generated files are newer than configure... done
     configure: creating ./config.status
     config.status: creating Makefile
     config.status: executing depfiles commands
     make[1]: Leaving directory '/usr/src/packages/BUILD'
        dh_auto_build
     dh_auto_build: warning: Compatibility levels before 10 are deprecated (level 9 in use)
     	make -j1
     make[1]: Entering directory '/usr/src/packages/BUILD'
     Makefile:244: *** missing separator.  Stop.
     make[1]: Leaving directory '/usr/src/packages/BUILD'
     dh_auto_build: error: make -j1 returned exit code 2
     make: *** [debian/rules:7: build] Error 25
     dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2

To test this, you can install dash from experimental and re-run the
configure script.

Please replace non-POSIX features with their equivalents to make sure
the script runs with dash. Most common ones are usage of == instead of =
and for with arrays (not lists).