build system: produce link map. Rather useful when you

are wondering why your busybox is much bigger that you hoped for.

Makefile

@@ -563,7 +563,7 @@ busybox-all  := $(core-y) $(libs-y)
 # May be overridden by arch/$(ARCH)/Makefile
 quiet_cmd_busybox__ ?= LINK    $@
       cmd_busybox__ ?= $(srctree)/scripts/trylink $(CC) $(LDFLAGS) \
-      -o $@ \
+      -o $@ -Wl,-M \
       -Wl,--warn-common -Wl,--sort-common -Wl,--gc-sections \
       -Wl,--start-group $(busybox-all) -Wl,--end-group
 

scripts/trylink

@@ -6,7 +6,7 @@ try() {
     added="$1"
     shift
     $debug && echo "Trying: $* $added"
-    "$@" $added >/dev/null 2>&1 \
+    "$@" $added >busybox.map 2>busybox_ld.err \
     && exit 0
 }
 
@@ -14,5 +14,5 @@ try "" "$@"
 try "-lm" "$@"
 try "-lcrypt" "$@"
 try "-Wl,--start-group -lcrypt -lm -Wl,--end-group" "$@"
-# It failed. Rerun & let people see the error messages
-"$@" $added
+# It failed. Let people see the error messages
+cat busybox_ld.err