tools: fix stale archive members surviving a Kconfig-driven CSRCS change

During the Toybox port to NuttX, Claude noticed that changes in the
menuconfig weren't taking affect. This issue exists for a long time on
NuttX, in fact BayLibre's presentation from 2017 make jokes about our
building system not been reliable:
https://www.youtube.com/watch?v=XUJK2htXxKw&t=320s

Stale archive members from $(AR)'s additive-only behavior can linger
after Kconfig toggles change which files provide a symbol, causing dead
weight or "multiple definition" link errors on incremental builds.
Fixed by splitting ARCHIVE into two macros: ARCHIVE keeps the original
additive behavior for apps/libapps.a, which many independent
subdirectories contribute to across a build, while the new
ARCHIVE_REBUILD deletes then archives for the far more common case
of a single Makefile building its own self-contained $(OBJS)
- all 39 such call sites now use it.

Assisted-By: Claude Sonnet 5
Signed-off-by: Alan C. Assis <acassis@gmail.com>

arch/arm/src/Makefile

@@ -183,14 +183,14 @@ $(STARTUP_OBJS): %$(OBJEXT): %.c
 
 ifeq ($(CONFIG_BUILD_FLAT),y)
 $(BIN): $(STARTUP_OBJS) $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 else
 $(BIN): $(STARTUP_OBJS) $(UOBJS)
-	$(call ARCHIVE, $@, $(UOBJS))
+	$(call ARCHIVE_REBUILD, $@, $(UOBJS))
 endif
 
 $(KBIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board$(DELIM)libboard$(LIBEXT): FORCE
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/arm64/src/Makefile

@@ -147,14 +147,14 @@ $(STARTUP_OBJS): %$(OBJEXT): %.c
 
 ifeq ($(CONFIG_BUILD_FLAT),y)
 $(BIN): $(OBJS) $(STARTUP_OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 else
 $(BIN): $(UOBJS) $(STARTUP_OBJS)
-	$(call ARCHIVE, $@, $(UOBJS))
+	$(call ARCHIVE_REBUILD, $@, $(UOBJS))
 endif
 
 $(KBIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board$(DELIM)libboard$(LIBEXT): FORCE
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/avr/src/Makefile

@@ -86,7 +86,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 libarch$(LIBEXT): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT):
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/ceva/src/Makefile

@@ -125,10 +125,10 @@ $(sort $(COBJS) $(UCOBJS)): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN) $(KBIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 $(UBIN): $(UOBJS)
-	$(call ARCHIVE, $@, $(UOBJS))
+	$(call ARCHIVE_REBUILD, $@, $(UOBJS))
 
 board$(DELIM)libboard$(LIBEXT):
 ifeq ($(CONFIG_ARCH_XC5),y)

arch/hc/src/Makefile

@@ -98,7 +98,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 libarch$(LIBEXT): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT):
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/mips/src/Makefile

@@ -84,7 +84,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 libarch$(LIBEXT): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT):
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/misoc/src/Makefile

@@ -88,7 +88,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 libarch$(LIBEXT): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT):
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/or1k/src/Makefile

@@ -115,14 +115,14 @@ $(COBJS) $(UCOBJS): %$(OBJEXT): %.c
 
 ifeq ($(CONFIG_BUILD_FLAT),y)
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 else
 $(BIN): $(UOBJS)
-	$(call ARCHIVE, $@, $(UOBJS))
+	$(call ARCHIVE_REBUILD, $@, $(UOBJS))
 endif
 
 $(KBIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board$(DELIM)libboard$(LIBEXT):
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/renesas/src/Makefile

@@ -92,7 +92,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 libarch$(LIBEXT): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT):
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/risc-v/src/Makefile

@@ -148,14 +148,14 @@ $(STARTUP_OBJS): %$(OBJEXT): %.c
 
 ifeq ($(CONFIG_BUILD_FLAT),y)
 $(BIN): $(STARTUP_OBJS) $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 else
 $(BIN): $(STARTUP_OBJS) $(UOBJS)
-	$(call ARCHIVE, $@, $(UOBJS))
+	$(call ARCHIVE_REBUILD, $@, $(UOBJS))
 endif
 
 $(KBIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT): FORCE
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/sim/src/Makefile

@@ -417,7 +417,7 @@ $(HOSTMOBJS): %$(OBJEXT): %.m
 # The architecture-specific library
 
 libarch$(LIBEXT): $(NUTTXOBJS)
-	$(call ARCHIVE, $@, $(NUTTXOBJS))
+	$(call ARCHIVE_REBUILD, $@, $(NUTTXOBJS))
 
 # The "board"-specific library. Of course, there really are no boards in
 # the simulation.  However, this is a good place to keep parts of the simulation

arch/sparc/src/Makefile

@@ -101,7 +101,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 libarch$(LIBEXT): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT):
 	$(Q) $(MAKE) -C board TOPDIR="$(TOPDIR)" libboard$(LIBEXT) EXTRADEFINES=$(EXTRADEFINES)

arch/tricore/src/Makefile

@@ -147,14 +147,14 @@ $(COBJS) $(UCOBJS) $(HEAD_COBJ): %$(OBJEXT): %.c
 
 ifeq ($(CONFIG_BUILD_FLAT),y)
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 else
 $(BIN): $(UOBJS)
-	$(call ARCHIVE, $@, $(UOBJS))
+	$(call ARCHIVE_REBUILD, $@, $(UOBJS))
 endif
 
 $(KBIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board$(DELIM)libboard$(LIBEXT):
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/x86/src/Makefile

@@ -110,7 +110,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 libarch$(LIBEXT): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT):
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/x86_64/src/Makefile

@@ -120,14 +120,14 @@ $(STARTUP_OBJS): %$(OBJEXT): %.c
 
 ifeq ($(CONFIG_BUILD_FLAT),y)
 $(BIN): $(OBJS) $(STARTUP_OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 else
 $(BIN): $(UOBJS) $(STARTUP_OBJS)
-	$(call ARCHIVE, $@, $(UOBJS))
+	$(call ARCHIVE_REBUILD, $@, $(UOBJS))
 endif
 
 $(KBIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT): FORCE
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/xtensa/src/Makefile

@@ -150,14 +150,14 @@ $(STARTUP_ELF_OBJS): %$(OBJEXT): %.c
 
 ifeq ($(CONFIG_BUILD_FLAT),y)
 $(BIN): $(STARTUP_ELF_OBJS) $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 else
 $(BIN): $(STARTUP_ELF_OBJS) $(UOBJS)
-	$(call ARCHIVE, $@, $(UOBJS))
+	$(call ARCHIVE_REBUILD, $@, $(UOBJS))
 endif
 
 $(KBIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT): FORCE
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

arch/z16/src/Makefile

@@ -78,7 +78,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 libarch$(LIBEXT): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 board/libboard$(LIBEXT):
 	$(Q) $(MAKE) -C board libboard$(LIBEXT) EXTRAFLAGS="$(EXTRAFLAGS)"

audio/Makefile

@@ -54,7 +54,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 makedepfile: $(CSRCS:.c=.ddc) $(ASRCS:.S=.dds)
 	$(call CATFILE, Make.dep, $^)

binfmt/Makefile

@@ -82,7 +82,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 makedepfile: $(CSRCS:.c=.ddc) $(ASRCS:.S=.dds)
 	$(call CATFILE, Make.dep, $^)

boards/Makefile

@@ -64,7 +64,7 @@ $(CXXOBJS): %$(OBJEXT): %.cxx
 	$(call COMPILEXX, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 makedepfile: $(CSRCS:.c=.ddc) $(ASRCS:.S=.dds) $(CXXSRCS:.cxx=.ddx)
 	$(call CATFILE, Make.dep, $^)

crypto/Makefile

@@ -102,7 +102,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 makedepfile: $(CSRCS:.c=.ddc) $(ASRCS:.S=.dds)
 	$(call CATFILE, Make.dep, $^)

drivers/Makefile

@@ -108,7 +108,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 context::
 

fs/Makefile

@@ -89,7 +89,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 context::
 

graphics/Makefile

@@ -105,7 +105,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 mklibgraphics: $(BIN)
 

libs/libbuiltin/Makefile

@@ -66,7 +66,7 @@ context:: bin kbin
 depend:: .depend
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 # C library for the kernel phase of the two-pass kernel build
 

libs/libc/Makefile

@@ -161,7 +161,7 @@ $(COBJS): $(BINDIR)$(DELIMS)%$(OBJEXT): %.c
 # the user phase of the two-pass kernel build
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 ifeq ($(CONFIG_LIBC_ZONEINFO_ROMFS),y)
 	$(Q) $(MAKE) -C zoneinfo all BIN=$(BIN)
 endif

libs/libc/zoneinfo/Makefile

@@ -48,7 +48,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 .built: .tzbuilt romfs $(OBJS)
-	$(call ARCHIVE, ..$(DELIM)$(BIN), $(OBJS))
+	$(call ARCHIVE_REBUILD, ..$(DELIM)$(BIN), $(OBJS))
 	$(Q) touch .built
 
 # ROMFS file system containing the TZ database

libs/libdsp/Makefile

@@ -62,7 +62,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 makedepfile: $(CSRCS:.c=.ddc) $(ASRCS:.S=.dds)
 	$(call CATFILE, Make.dep, $^)

libs/libm/Makefile

@@ -56,7 +56,7 @@ $(COBJS): $(BINDIR)$(DELIM)$(DELIM)%$(OBJEXT): %.c
 # the user phase of the two-pass kernel build
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 # math library for the kernel phase of the two-pass kernel build
 

libs/libnx/Makefile

@@ -216,7 +216,7 @@ $(COBJS): $(BINDIR)$(DELIM)%$(OBJEXT): %.c
 # the user phase of the two-pass kernel build
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 # NX library for the kernel phase of the two-pass kernel build
 

libs/libxx/Makefile

@@ -77,7 +77,7 @@ $(CPPOBJS): %$(OBJEXT): %.cpp
 	$(call COMPILEXX, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 context::
 

mm/Makefile

@@ -80,7 +80,7 @@ $(COBJS): $(BINDIR)$(DELIMS)%$(OBJEXT): %.c
 # the user phase of the two-pass kernel build
 
 $(BIN):	$(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 # Memory manager for the kernel phase of the two-pass kernel build
 

net/Makefile

@@ -86,7 +86,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 makedepfile: $(CSRCS:.c=.ddc) $(ASRCS:.S=.dds)
 	$(call CATFILE, Make.dep, $^)

openamp/Makefile

@@ -46,7 +46,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 context::
 

pass1/Makefile

@@ -43,7 +43,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 makedepfile: $(CSRCS:.c=.ddc) $(ASRCS:.S=.dds)
 	$(call CATFILE, Make.dep, $^)

sched/Makefile

@@ -65,7 +65,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 makedepfile: $(CSRCS:.c=.ddc) $(ASRCS:.S=.dds)
 	$(call CATFILE, Make.dep, $^)

syscall/Makefile

@@ -72,13 +72,13 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN1): $(PROXY_OBJS)
-	$(call ARCHIVE, $@, $(PROXY_OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(PROXY_OBJS))
 
 $(BIN2): $(STUB_OBJS)
-	$(call ARCHIVE, $@, $(STUB_OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(STUB_OBJS))
 
 $(BIN3): $(WRAP_OBJS)
-	$(call ARCHIVE, $@, $(WRAP_OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(WRAP_OBJS))
 
 $(SYSCALLWRAPS): .context
 

tools/Config.mk

@@ -443,6 +443,21 @@ endef
 # Note: The fileN strings may not contain spaces or  characters that may be
 # interpreted strangely by the shell
 #
+# Purely additive: $(AR) only adds or replaces the members it's given, it
+# never removes anything already in the archive. That's exactly right for
+# a target that many independent callers each contribute a partial object
+# list to over the life of a build (apps/libapps.a, built up one
+# subdirectory's objects at a time via apps/Make.defs' ARLOCK, which wraps
+# this same macro as `flock $1.lock $(call ARCHIVE, $1, $2)` to serialize
+# concurrent contributions under -j) -- rebuilding from scratch on every
+# call would only ever leave the last contributor's objects behind. Use
+# ARCHIVE_REBUILD instead for the other shape: a single Makefile archiving
+# its own complete, self-contained object list in one call.
+#
+# This has to stay a single command, not two separate recipe lines: flock
+# execs its argument directly rather than handing it to a shell, so a
+# second recipe line here would run outside the lock entirely.
+#
 # Depends on these settings defined in board-specific Make.defs file
 # installed at $(TOPDIR)/Make.defs:
 #
@@ -457,6 +472,41 @@ define ARCHIVE
 	$(AR) $1  $2
 endef
 
+# ARCHIVE_REBUILD - Replace an archive's entire contents with a list of files
+# Example: $(call ARCHIVE_REBUILD, archive-file, "file1 file2 file3 ...")
+#
+# For the common case ARCHIVE itself doesn't cover: a single Makefile
+# archiving its own complete object list ($(OBJS), derived from CSRCS/
+# ASRCS) in one call, as nearly every "$(BIN): $(OBJS)" rule in the tree
+# does (libs/libc, libs/libm, sched, drivers, fs, mm, net, graphics,
+# video, binfmt, crypto, boards, arch/*/src, ...). There, $2 is meant to
+# be the archive's entire, authoritative contents, not one contribution
+# among several -- so remove any pre-existing archive-file first. Without
+# that, a Kconfig change that alters which files CSRCS puts in $2 (e.g.
+# one implementation of a function replacing another under a different
+# filename) leaves whatever was archived under the old configuration
+# lingering in the .a indefinitely across an incremental build: best case
+# dead weight, worst case a stale, outdated definition the linker picks up
+# instead of the current one, silently or as a "multiple definition" error
+# if the two coexist. Rebuilding the archive from scratch every time this
+# rule fires costs a few milliseconds even for a large (700+ member)
+# library, which is worth paying to not carry that risk.
+#
+# Depends on these settings defined in board-specific Make.defs file
+# installed at $(TOPDIR)/Make.defs:
+#
+#   AR - The command to invoke the archiver (includes any options)
+#
+# Depends on this settings defined in board-specific defconfig file installed
+# at $(TOPDIR)/.config:
+#
+#   CONFIG_WINDOWS_NATIVE - Defined for a Windows native build
+
+define ARCHIVE_REBUILD
+	$(Q) rm -f $1
+	$(AR) $1  $2
+endef
+
 # PRELINK - Prelink a list of files
 # This is useful when files were compiled with fvisibility=hidden.
 # Any symbol which was not explicitly made global is invisible outside the

video/Makefile

@@ -48,7 +48,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 makedepfile: $(CSRCS:.c=.ddc) $(ASRCS:.S=.dds)
 	$(call CATFILE, Make.dep, $^)

wireless/Makefile

@@ -46,7 +46,7 @@ $(COBJS): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 
 $(BIN): $(OBJS)
-	$(call ARCHIVE, $@, $(OBJS))
+	$(call ARCHIVE_REBUILD, $@, $(OBJS))
 
 makedepfile: $(CSRCS:.c=.ddc) $(ASRCS:.S=.dds)
 	$(call CATFILE, Make.dep, $^)