package/skeleton: also handle merged /usr in the staging

When the target uses a merged /usr setup, gdbserver will only report
paths in /lib to the remote gdb, which in turn will only look for
libraries in staging/lib and never in staging/usr/lib.

So. the merged (or non-merged) /usr setup must be replicated in the
staging.

The best solution where to do so is in the skeleton package, since it
is guaranteed to come before any package that installs things in the
staging, and even before the (internal or external) toolchain as well.

Reported-by: Pieterjan Camerlynck <pieterjan.camerlynck@gmail.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Pieterjan Camerlynck <pieterjan.camerlynck@gmail.com>
Cc: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Cc: Peter Korsgaard <jacmet@uclibc.org>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

Makefile

@@ -456,14 +456,9 @@ else
 LIB_SYMLINK = lib32
 endif
 
+# Populating the staging with the base directories is handled by the skeleton package
 $(STAGING_DIR):
-	@mkdir -p $(STAGING_DIR)/bin
-	@mkdir -p $(STAGING_DIR)/lib
-	@ln -snf lib $(STAGING_DIR)/$(LIB_SYMLINK)
-	@mkdir -p $(STAGING_DIR)/usr/lib
-	@ln -snf lib $(STAGING_DIR)/usr/$(LIB_SYMLINK)
-	@mkdir -p $(STAGING_DIR)/usr/include
-	@mkdir -p $(STAGING_DIR)/usr/bin
+	@mkdir -p $(STAGING_DIR)
 	@ln -snf $(STAGING_DIR) $(BASE_DIR)/staging
 
 RSYNC_VCS_EXCLUSIONS = \

package/skeleton/skeleton.mk

@@ -13,6 +13,9 @@ SKELETON_SOURCE =
 # on skeleton.
 SKELETON_ADD_TOOLCHAIN_DEPENDENCY = NO
 
+# The skeleton also handles the merged /usr case in the sysroot
+SKELETON_INSTALL_STAGING = YES
+
 ifeq ($(BR2_ROOTFS_SKELETON_CUSTOM),y)
 
 SKELETON_PATH = $(call qstrip,$(BR2_ROOTFS_SKELETON_CUSTOM_PATH))
@@ -85,6 +88,21 @@ define SKELETON_INSTALL_TARGET_CMDS
 		$(TARGET_DIR_WARNING_FILE)
 endef
 
+# For the staging dir, we don't really care about /bin and /sbin.
+# But for consistency with the target dir, and to simplify the code,
+# we still handle them for the merged or non-merged /usr cases.
+# Since the toolchain is not yet available, the staging is not yet
+# populated, so we need to create the directories in /usr
+define SKELETON_INSTALL_STAGING_CMDS
+	$(INSTALL) -d -m 0755 $(STAGING_DIR)/usr/lib
+	$(INSTALL) -d -m 0755 $(STAGING_DIR)/usr/bin
+	$(INSTALL) -d -m 0755 $(STAGING_DIR)/usr/sbin
+	$(INSTALL) -d -m 0755 $(STAGING_DIR)/usr/include
+	$(call SKELETON_USR_SYMLINKS_OR_DIRS,$(STAGING_DIR))
+	ln -snf lib $(STAGING_DIR)/$(LIB_SYMLINK)
+	ln -snf lib $(STAGING_DIR)/usr/$(LIB_SYMLINK)
+endef
+
 SKELETON_TARGET_GENERIC_HOSTNAME = $(call qstrip,$(BR2_TARGET_GENERIC_HOSTNAME))
 SKELETON_TARGET_GENERIC_ISSUE = $(call qstrip,$(BR2_TARGET_GENERIC_ISSUE))
 SKELETON_TARGET_GENERIC_ROOT_PASSWD = $(call qstrip,$(BR2_TARGET_GENERIC_ROOT_PASSWD))