add implicit rule for %.a to help debugging in subdirs

git-svn-id: svn://busybox.net/trunk/busybox@15057 69ca8d6d-28ef-0310-b511-8ec308f3f277

1 files changed, 8 insertions, 0 deletions

diff --git a/Rules.mak b/Rules.mak
index 17e136712..ff6ea32db 100644
--- a/Rules.mak
+++ b/Rules.mak
@@ -353,4 +353,12 @@ do_elf2flt         = @$(disp_elf2flt)   ; $(cmd_elf2flt)
 %.o: %.c
         $(compile.c)
 
+uppercase = $(shell echo $1 | tr '[:lower:]' '[:upper:]')
+%.a:
+        @if test -z "$($(call uppercase,$*)_DIR)" ; then \
+                echo "Invalid target $@" ; \
+                exit 1 ; \
+        fi
+        $(Q)$(MAKE) $($(call uppercase,$*)_DIR)$@
+
 .PHONY: dummy