Switch from archive libraries to partial linking

Before this commit, weak symbols were not overridden by non-weak symbols
found in archive libraries when linking with recent versions of
binutils.  As stated in the System V ABI, "the link editor does not
extract archive members to resolve undefined weak symbols".

This commit changes all Makefiles to use partial linking (ld -r) instead
of creating library archives, which forces all symbols to participate in
linking, allowing non-weak symbols to override weak symbols as intended.
This approach is also used by Linux, from which the gmake function
cmd_link_o_target (defined in config.mk and used in all Makefiles) is
inspired.

The name of each former library archive is preserved except for
extensions which change from ".a" to ".o".  This commit updates
references accordingly where needed, in particular in some linker
scripts.

This commit reveals board configurations that exclude some features but
include source files that depend these disabled features in the build,
resulting in undefined symbols.  Known such cases include:
- disabling CMD_NET but not CMD_NFS;
- enabling CONFIG_OF_LIBFDT but not CONFIG_QE.

Signed-off-by: Sebastien Carlier <sebastien.carlier@gmail.com>

8 files changed, 16 insertions, 16 deletions

diff --git a/fs/cramfs/Makefile b/fs/cramfs/Makefile
index 7b6cc0ad3..5f419329a 100644
--- a/fs/cramfs/Makefile
+++ b/fs/cramfs/Makefile
@@ -23,7 +23,7 @@
 
 include $(TOPDIR)/config.mk
 
-LIB	= $(obj)libcramfs.a
+LIB	= $(obj)libcramfs.o
 
 AOBJS	=
 COBJS-$(CONFIG_CMD_CRAMFS) := cramfs.o
@@ -37,7 +37,7 @@ OBJS	:= $(addprefix $(obj),$(AOBJS) $(COBJS-y))
 all:	$(LIB) $(AOBJS)
 
 $(LIB):	$(obj).depend $(OBJS)
-	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 
 #########################################################################
diff --git a/fs/ext2/Makefile b/fs/ext2/Makefile
index 712e34839..3c65d252f 100644
--- a/fs/ext2/Makefile
+++ b/fs/ext2/Makefile
@@ -27,7 +27,7 @@
 
 include $(TOPDIR)/config.mk
 
-LIB	= $(obj)libext2fs.a
+LIB	= $(obj)libext2fs.o
 
 AOBJS	=
 COBJS-$(CONFIG_CMD_EXT2) := ext2fs.o dev.o
@@ -40,7 +40,7 @@ OBJS	:= $(addprefix $(obj),$(AOBJS) $(COBJS-y))
 all:	$(LIB) $(AOBJS)
 
 $(LIB):	$(obj).depend $(OBJS)
-	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 #########################################################################
 
diff --git a/fs/fat/Makefile b/fs/fat/Makefile
index b711460f3..bc459662e 100644
--- a/fs/fat/Makefile
+++ b/fs/fat/Makefile
@@ -21,7 +21,7 @@
 
 include $(TOPDIR)/config.mk
 
-LIB	= $(obj)libfat.a
+LIB	= $(obj)libfat.o
 
 AOBJS	=
 COBJS-$(CONFIG_CMD_FAT)	:= fat.o file.o
@@ -32,7 +32,7 @@ OBJS	:= $(addprefix $(obj),$(AOBJS) $(COBJS-y))
 all:	$(LIB) $(AOBJS)
 
 $(LIB):	$(obj).depend $(OBJS)
-	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 
 #########################################################################
diff --git a/fs/fdos/Makefile b/fs/fdos/Makefile
index fce2032bd..9cd4d9174 100644
--- a/fs/fdos/Makefile
+++ b/fs/fdos/Makefile
@@ -28,7 +28,7 @@
 
 include $(TOPDIR)/config.mk
 
-LIB	= $(obj)libfdos.a
+LIB	= $(obj)libfdos.o
 
 AOBJS	=
 COBJS-$(CONFIG_CMD_FDOS) := fat.o vfat.o dev.o fdos.o fs.o subdir.o
@@ -41,7 +41,7 @@ OBJS	:= $(addprefix $(obj),$(AOBJS) $(COBJS-y))
 all:	$(LIB) $(AOBJS)
 
 $(LIB):	$(obj).depend $(OBJS)
-	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 
 #########################################################################
diff --git a/fs/jffs2/Makefile b/fs/jffs2/Makefile
index 7c9fb41b8..6db6145d2 100644
--- a/fs/jffs2/Makefile
+++ b/fs/jffs2/Makefile
@@ -23,7 +23,7 @@
 
 include $(TOPDIR)/config.mk
 
-LIB	= $(obj)libjffs2.a
+LIB	= $(obj)libjffs2.o
 
 AOBJS	=
 ifdef CONFIG_CMD_JFFS2
@@ -44,7 +44,7 @@ OBJS	:= $(addprefix $(obj),$(AOBJS) $(COBJS))
 all:	$(LIB) $(AOBJS)
 
 $(LIB):	$(obj).depend $(OBJS)
-	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 
 #########################################################################
diff --git a/fs/reiserfs/Makefile b/fs/reiserfs/Makefile
index 9cef8ee91..495759c8c 100644
--- a/fs/reiserfs/Makefile
+++ b/fs/reiserfs/Makefile
@@ -27,7 +27,7 @@
 
 include $(TOPDIR)/config.mk
 
-LIB	= $(obj)libreiserfs.a
+LIB	= $(obj)libreiserfs.o
 
 AOBJS	=
 COBJS-$(CONFIG_CMD_REISER) := reiserfs.o dev.o mode_string.o
@@ -40,7 +40,7 @@ OBJS	:= $(addprefix $(obj),$(AOBJS) $(COBJS-y))
 all:	$(LIB) $(AOBJS)
 
 $(LIB):	$(obj).depend $(OBJS)
-	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 #########################################################################
 
diff --git a/fs/ubifs/Makefile b/fs/ubifs/Makefile
index 8328843fe..ccffe85ee 100644
--- a/fs/ubifs/Makefile
+++ b/fs/ubifs/Makefile
@@ -27,7 +27,7 @@
 
 include $(TOPDIR)/config.mk
 
-LIB	= $(obj)libubifs.a
+LIB	= $(obj)libubifs.o
 
 COBJS-$(CONFIG_CMD_UBIFS) := ubifs.o io.o super.o sb.o master.o lpt.o
 COBJS-$(CONFIG_CMD_UBIFS) += lpt_commit.o scan.o lprops.o
@@ -40,7 +40,7 @@ OBJS	:= $(addprefix $(obj),$(AOBJS) $(COBJS-y))
 all:	$(LIB) $(AOBJS)
 
 $(LIB):	$(obj).depend $(OBJS)
-	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 #########################################################################
 
diff --git a/fs/yaffs2/Makefile b/fs/yaffs2/Makefile
index a2ef5e22f..7753cfcf3 100644
--- a/fs/yaffs2/Makefile
+++ b/fs/yaffs2/Makefile
@@ -19,7 +19,7 @@
 #EXTRA_COMPILE_FLAGS = -DYAFFS_IGNORE_TAGS_ECC
 include $(TOPDIR)/config.mk
 
-LIB = $(obj)libyaffs2.a
+LIB = $(obj)libyaffs2.o
 
 COBJS-$(CONFIG_YAFFS2) := \
 	yaffscfg.o yaffs_ecc.o yaffsfs.o yaffs_guts.o yaffs_packedtags1.o \
@@ -36,7 +36,7 @@ CFLAGS +=    -DCONFIG_YAFFS_DIRECT -DCONFIG_YAFFS_SHORT_NAMES_IN_RAM -DCONFIG_YA
 all:  $(LIB)
 
 $(LIB): $(obj).depend $(OBJS)
-	$(AR) $(ARFLAGS) $@ $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
 
 .PHONY: clean distclean
 clean: