lib.mk: make sure archive file contains only specified objects

The recipe for archive (.a) files is updated so we won't try to append
objects to an existing archive left over from a previous build.

This fixes the following build error:
 $ make -s PLATFORM=hikey
 $ make -s PLATFORM=hikey CFG_ARM64_core=y \
     CROSS_COMPILE_core=aarch64-linux-gnu-
 [...]libtomcrypt.a: error adding symbols: File in wrong format

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Pascal Brand <pascal.brand@linaro.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/mk/lib.mk b/mk/lib.mk
index 70fcd44d..87cf5798 100644
--- a/mk/lib.mk
+++ b/mk/lib.mk
@@ -32,7 +32,7 @@ else
 $(lib-libfile): $(objs)
 	@$(cmd-echo-silent) '  AR      $$@'
 	@mkdir -p $$(dir $$@)
-	$$(q)$$(AR$(sm)) rcs $$@ $$^
+	$$(q)rm -f $$@ && $$(AR$(sm)) rcs $$@ $$^
 endif
 endef #process-lib