tool/run: way to obtain list of build artifacts

The new function 'build_artifacts' returns a list of artifacts created
by the Genode build system. The list can be supplied as argument to
the 'build_boot_image' function.

Note that the list covers only program targets and shared libraries.
Other artifacts created as side effects of custom rules are not covered.

Fixes #4368

tool/run/run

@@ -44,6 +44,8 @@ proc assert_spec {spec} {
 #
 proc build {targets} {
 
+	global _collected_build_artifacts
+
 	if {[llength $targets] == 0} return
 
 	if {[get_cmd_switch --skip-build]} return
@@ -57,10 +59,33 @@ proc build {targets} {
 		puts "Error: Genode build failed"
 		exit -4
 	}
+
+	# record the build artifacts created during the build process
+	set artifacts_log [exec sed -n "/^#/s/^# Build artifact //p" progress.log]
+	lappend _collected_build_artifacts {*}[split $artifacts_log "\n"]
+
 	puts "genode build completed"
 }
 
 
+##
+# Return list of build artifacts created during 'build'
+#
+# The returned artifacts can be used as boot-modules arguments for
+# the 'build_boot_image' step.
+#
+proc build_artifacts { } {
+
+	global _collected_build_artifacts
+
+	if {![info exists _collected_build_artifacts]} {
+		return { } }
+
+	# use lsort to remove duplicates
+	return [lsort -unique $_collected_build_artifacts]
+}
+
+
 ##
 # Create a fresh boot directory
 #