Overhaul build system and add support for disabling inetd support.

This patch adds support for a configure script and with it
support for disabling inetd support.  See the output from

    ./configure --help

* Add configure script
* Sprinkle #ifdef fairy dust on svc.c when inetd support is disabled
* Use GCC built-in autodep calculator (-MMD -MP)
* Fix name space issue with include files, use relative paths
* Disable username/group name to uid/gid functions in static builds
* Bug out (error) if a user tries to build the bootmisc plugin static

Possibly fixes GitHub issue #5 and issue #6.

NOTE: The static build has not received any testing at all!

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

plugins/Makefile

@@ -1,24 +1,23 @@
 # Plugin based services architecture for finit
-CFLAGS     += -fPIC -Os
-CPPFLAGS   += -I..
+TOPDIR     ?= $(shell pwd)
+CFLAGS     += -fPIC
 LDFLAGS    := $(filter-out -rdynamic, $(LDFLAGS))
 LDFLAGS    += -shared
 ifneq ($(STATIC), 1)
 PLUGINS    ?= initctl.so alsa-utils.so bootmisc.so dbus.so hwclock.so \
 	      resolvconf.so urandom.so x11-common.so tty.so time.so
-DEPS        = $(addprefix .,$(PLUGINS:.so=.d))
+DEPS       := $(PLUGINS:.so=.d)
 endif
-TOPDIR     ?= $(shell pwd)
 
 include ../common.mk
 
 all: $(PLUGINS)
 
 clean:
-	-@$(RM) $(PLUGINS) *.o
+	-@$(RM) $(PLUGINS)
 
-distclean: clean
-	-@$(RM) $(JUNK) $(DEPS)
+distclean:
+	-@$(RM) *.o *.so $(JUNK) $(DEPS)
 
 install: all
 	@install -d $(DESTDIR)$(plugindir)
@@ -34,6 +33,6 @@ uninstall:
 	done
 	-@rmdir $(DESTDIR)$(plugindir) 2>/dev/null
 
-ifneq ($(MAKECMDGOALS),clean)
- -include $(DEPS)
+ifneq ($(MAKECMDGOALS),distclean)
+-include $(DEPS)
 endif