feat(pm/dpkg): introduce @AB_SPIRAL_PROVIDES@ placeholder

pm/dpkg.sh

@@ -51,10 +51,18 @@ dpkgfield() {
 		    local _data
 			_data="$(dpkg_get_provides "${__AB_SO_DEPS[@]}")"
 			abdbg "Auto dependency discovery found: ${_data}" >&2
-			while read -r LINE; do
+		  while read -r LINE; do
 				_string_v+=("$LINE")
 			done <<< "${_data}"
 		fi
+		if [ "${_v}" = "@AB_SPIRAL_PROVIDES@" ]; then
+      if ! ((${#__AB_SPIRAL_PROVIDES})); then
+        abdie "Spiral provides generation requested, but no shared library found!" >&2
+      fi
+      for SPIRAL_PROV in "${__AB_SPIRAL_PROVIDES[@]}"; do
+        _string_v+=("$SPIRAL_PROV (= 0:$(dpkgpkgver))")
+      done
+		fi
 	done
 	# second-pass: actually fill in the blanks
 	local _buffer=()