system_manager, libobmc-intf: Add power GPIO configuration interface

This adds a dbus call (in org.openbmc.managers.System) and C binding (in
libopenbmc-intf) to read a POWER_CONFIG from the Python system
configuration that abstracts GPIO functionality (power good, reset, etc)
from their net names in GPIO_CONFIG.

This should eventually replace machine-specific patches to op-pwrctl
that define their own power and reset lines.

Change-Id: I56eaaf60ef852b68124e4a765942243ad17d06ac
Signed-off-by: Xo Wang <xow@google.com>
diff --git a/libopenbmc_intf/Makefile b/libopenbmc_intf/Makefile
index cd86906..fe17dc9 100644
--- a/libopenbmc_intf/Makefile
+++ b/libopenbmc_intf/Makefile
@@ -5,7 +5,7 @@
 SONAME=libopenbmc_intf.so
 VERSION=1
 LIBOBMC=$(SONAME).$(VERSION)
-INCLUDES=openbmc_intf.h openbmc.h gpio.h
+INCLUDES=openbmc_intf.h openbmc.h gpio.h power_gpio.h
 
 LDLIBS+=$(shell pkg-config --libs $(PACKAGE_DEPS))
 ALL_CFLAGS+=$(shell pkg-config --cflags $(PACKAGE_DEPS)) -fPIC -Werror $(CFLAGS)
@@ -18,7 +18,7 @@
 $(SONAME): $(LIBOBMC)
 	ln -sf $^ $@
 
-$(LIBOBMC): lib%.so.$(VERSION): %.o gpio.o
+$(LIBOBMC): lib%.so.$(VERSION): %.o gpio.o power_gpio.o
 	$(CC) -shared $(CFLAGS) $(LDFLAGS) -Wl,-soname,$(SONAME) \
 		-o $@ $^ $(LDLIBS)