Don't hardcode commands paths

Don't assume that utilities such as systemctl or initctl is found in a certain
specific path. Instead look for them in $PATH. This applies to both the
Makefile and the NetworkManager dispatcher script.

Resolves #11.

Makefile

@@ -1,20 +1,26 @@
+APT_GET:=$(shell which apt-get)
+DNF_OR_YUM:=$(shell which dnf || which yum)
+INITCTL:=$(shell which initctl)
+SYSTEMCTL:=$(shell which systemctl)
+TAYGA:=$(shell which tayga)
+
 install:
 	# Install the main script to /usr/sbin
 	install -m0755 clatd /usr/sbin/clatd
 	# Install manual page if pod2man is installed
 	pod2man --name clatd --center "clatd - a CLAT implementation for Linux" --section 8 README.pod /usr/share/man/man8/clatd.8 && gzip -f9 /usr/share/man/man8/clatd.8 || echo "pod2man is required to generate manual page"
 	# Install systemd service file if applicable for this system
-	if test -x /usr/bin/systemctl && test -d "/etc/systemd/system"; then install -m0644 scripts/clatd.systemd /etc/systemd/system/clatd.service && systemctl daemon-reload; fi
+	if test -x "$(SYSTEMCTL)" && test -d "/etc/systemd/system"; then install -m0644 scripts/clatd.systemd /etc/systemd/system/clatd.service && $(SYSTEMCTL) daemon-reload; fi
-	if test -e "/etc/systemd/system/clatd.service" && test ! -e "/etc/systemd/system/multi-user.target.wants/clatd.service"; then systemctl enable clatd.service; fi
+	if test -e "/etc/systemd/system/clatd.service" && test ! -e "/etc/systemd/system/multi-user.target.wants/clatd.service"; then $(SYSTEMCTL) enable clatd.service; fi
 	# Install upstart service file if applicable for this system
-	if test -x /sbin/initctl && test -d "/etc/init"; then install -m0644 scripts/clatd.upstart /etc/init/clatd.conf; fi
+	if test -x "$(INITCTL)" && test -d "/etc/init"; then install -m0644 scripts/clatd.upstart /etc/init/clatd.conf; fi
 	# Install NetworkManager dispatcher script if applicable
 	if test -d /etc/NetworkManager/dispatcher.d; then install -m0755 scripts/clatd.networkmanager /etc/NetworkManager/dispatcher.d/50-clatd; fi
 
 installdeps:
 	# .deb/apt-get based distros
-	if test -x /usr/bin/apt-get; then apt-get -y install perl-base perl-modules libnet-ip-perl libnet-dns-perl libio-socket-inet6-perl iproute iptables tayga; fi
+	if test -x "$(APT_GET)"; then $(APT_GET) -y install perl-base perl-modules libnet-ip-perl libnet-dns-perl libio-socket-inet6-perl iproute iptables tayga; fi
-	# .rpm/YUM-based distros
+	# .rpm/DNF/YUM-based distros
-	if test -x /usr/bin/yum; then yum -y install perl perl-Net-IP perl-Net-DNS perl-IO-Socket-INET6 perl-File-Temp iproute iptables; fi
+	if test -x "$(DNF_OR_YUM)"; then $(DNF_OR_YUM) -y install perl perl-Net-IP perl-Net-DNS perl-IO-Socket-INET6 perl-File-Temp iproute iptables; fi
-	# to get TAYGA on .rpm/YUM-based distros, we unfortunately need to install from source
+	# If necessary, try to install the TAYGA .rpm using dnf/yum. It is unfortunately not available in all .rpm based distros (in particular CentOS/RHEL).
-	if test -x /usr/bin/yum && test ! -x /usr/sbin/tayga; then echo "TAYGA isn't packaged for YUM-based distros, will download and compile the source in 5 seconds (^C interrupts)" && sleep 5 && yum -y install gcc tar wget bzip2 && wget http://www.litech.org/tayga/tayga-0.9.2.tar.bz2 && bzcat tayga-0.9.2.tar.bz2 | tar x && cd tayga-0.9.2 && ./configure --prefix=/usr && make && make install && rm -rf ../tayga-0.9.2.tar.bz2 ../tayga-0.9.2; fi
+	if test -x "$(DNF_OR_YUM)" && test ! -x "$(TAYGA)"; then $(DNF_OR_YUM) -y install tayga || echo "ERROR: Failed to install TAYGA using dnf/yum, the package is probably not included in your distro. Try enabling the EPEL repo <URL: https://fedoraproject.org/wiki/EPEL> and try again, or install TAYGA <URL: http://www.litech.org/tayga> directly from source."; exit 1; fi

scripts/clatd.networkmanager

@@ -26,8 +26,8 @@
 # start from scratch than to figure out if a restart is truly necessary
 
 # systemd-based distros
-if test -x /usr/bin/systemctl; then
+if which systemctl &> /dev/null; then
-  /usr/bin/systemctl restart clatd.service
+  systemctl restart clatd.service
 fi
 
 # upstart-based distros