Remove phpdbg binary during make clean

[arnaud-lb]

make clean does not remove the phpdbg binary. This is annoying because after rebuilding without phpdbg, make test will attempt to run phpdbg tests, which will fail if the binary is not compatible with extensions. E.g.:

./configure && make
make clean

./configure --disable-phpdbg --enable-zts && make

# phpdbg tests are not skipped because the binary exists
# but they fail because extensions can not be loaded
make test

[petk]

Indeed. Thanks for syncing this.