HOST_DIR/lib: symlink respectively to lib32/64

Discovered the issue on a RHEL7.4 machine where
the cmake build dynamically selected HOST_DIR/lib64
as the installation path for the lzo2 library.

Fixes failures like the following:
host-mtd
http://autobuild.buildroot.net/results/d31/d31581d2e60f35cf70312683df99c768e2ea8516/

host-squashfs
http://autobuild.buildroot.net/results/d9c/d9c95231ac774ed71580754a15ebb3b121764310/

Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

Makefile

@@ -542,7 +542,7 @@ endif
 
 .PHONY: dirs
 dirs: $(BUILD_DIR) $(STAGING_DIR) $(TARGET_DIR) \
-	$(HOST_DIR) $(HOST_DIR)/usr $(BINARIES_DIR)
+	$(HOST_DIR) $(HOST_DIR)/usr $(HOST_DIR)/lib $(BINARIES_DIR)
 
 $(BUILD_DIR)/buildroot-config/auto.conf: $(BR2_CONFIG)
 	$(MAKE1) $(EXTRAMAKEARGS) HOSTCC="$(HOSTCC_NOCCACHE)" HOSTCXX="$(HOSTCXX_NOCCACHE)" silentoldconfig
@@ -565,6 +565,13 @@ sdk: world
 $(HOST_DIR)/usr: $(HOST_DIR)
 	@ln -snf . $@
 
+$(HOST_DIR)/lib: $(HOST_DIR)
+	@mkdir -p $@
+	@case $(HOSTARCH) in \
+		(*64) ln -snf lib $(@D)/lib64;; \
+		(*)   ln -snf lib $(@D)/lib32;; \
+	esac
+
 # Populating the staging with the base directories is handled by the skeleton package
 $(STAGING_DIR):
 	@mkdir -p $(STAGING_DIR)