Add tool to install/update sysroot

Signed-off-by: Louis-Francis Ratté-Boulianne <lfrb@collabora.com>

Differential Revision: https://phabricator.apertis.org/D4766

tools/Makefile

 INSTALL ?= install
 PREFIX ?= /usr
-ROOT_TOOLDIR ?= $(DESTDIR)$(PREFIX)/bin
+bindir = $(PREFIX)/bin
+ROOT_TOOLDIR ?= $(DESTDIR)$(bindir)
 
-TOOLS =
+TOOLS = \
+	ade
 
 all: