build: ensure device source file constructors can be linked and called

gcc's linker does not add constructors from object files to the main
executable if they are built into a convenience library and then the
library is linked to the executable, unless something outside of the
object file with the constructor references a symbol from the object
file.

http://osdir.com/ml/libtool-gnu/2011-06/msg00003.html

"Yes, when convenience libraries are used to create a shared library, all the
objects are included in the output, when the output is an application they are
used like a normal archive library.

Either use them to create a shared library or, if creating an application,
don't use them, use the objects instead."

Further patches will remove all references to the NMDevice subclasses
from nm-manager.c, and have each NMDevice subclass register itself
with a factory through a constructor.  But due to the above issue,
we need to somehow ensure the constructor in each nm-device-*.c file
gets added to the executable.  This is accomplished by explicitly
linking each NMDevice subclass' object file into the main executable.

(Note that we cannot use -Wl,-whole-archive here because libtool only
supports this option for linking a convenience library to a shared
library, but not to an executable, and will actively prevent using
-whole-archive in LDFLAGS)

1 files changed, 17 insertions, 10 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 494bc8ef3a..f0b22d2e29 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -55,21 +55,35 @@ AM_CPPFLAGS += $(foreach d,$(sort $(dir $(libNetworkManager_la_SOURCES))),-I$(to
 sbin_PROGRAMS = NetworkManager
 
 NetworkManager_SOURCES = \
+	$(nm_device_sources) $(nm_device_headers) \
 	main.c
 
 NetworkManager_LDADD = libNetworkManager.la
 
 noinst_LTLIBRARIES = libNetworkManager.la
 
+nm_device_sources = \
+	$(NULL)
+
+nm_device_headers = \
+	devices/nm-device-bond.h \
+	devices/nm-device-bridge.h \
+	devices/nm-device-ethernet.h \
+	devices/nm-device-gre.h \
+	devices/nm-device-infiniband.h \
+	devices/nm-device-macvlan.h \
+	devices/nm-device-tun.h \
+	devices/nm-device-veth.h \
+	devices/nm-device-vlan.h \
+	devices/nm-device-vxlan.h
+
 nm_sources = \
+	$(nm_device_headers) \
 	devices/nm-device.c \
 	devices/nm-device.h \
 	devices/nm-device-bond.c \
-	devices/nm-device-bond.h \
 	devices/nm-device-bridge.c \
-	devices/nm-device-bridge.h \
 	devices/nm-device-ethernet.c \
-	devices/nm-device-ethernet.h \
 	devices/nm-device-ethernet-utils.c \
 	devices/nm-device-ethernet-utils.h \
 	devices/nm-device-factory.c \
@@ -77,21 +91,14 @@ nm_sources = \
 	devices/nm-device-generic.c \
 	devices/nm-device-generic.h \
 	devices/nm-device-gre.c \
-	devices/nm-device-gre.h \
 	devices/nm-device-infiniband.c \
-	devices/nm-device-infiniband.h \
 	devices/nm-device-logging.h \
 	devices/nm-device-macvlan.c \
-	devices/nm-device-macvlan.h \
 	devices/nm-device-private.h \
 	devices/nm-device-tun.c \
-	devices/nm-device-tun.h \
 	devices/nm-device-veth.c \
-	devices/nm-device-veth.h \
 	devices/nm-device-vlan.c \
-	devices/nm-device-vlan.h \
 	devices/nm-device-vxlan.c \
-	devices/nm-device-vxlan.h \
 	\
 	dhcp-manager/nm-dhcp-client.c \
 	dhcp-manager/nm-dhcp-client.h \