zlib: disable call to ldconfig

By default, zlib installation procedure calls ldconfig, which takes
time uselessly. ldconfig is only useful if you install libraries on
the host (in directories listed in /etc/ld.so.conf, or in /usr/lib or
/lib), so calling it after installing libraries in $(STAGING_DIR),
$(TARGET_DIR) or $(HOST_DIR) is just a lenghty no-op.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/zlib/zlib.mk

@@ -48,15 +48,15 @@ define HOST_ZLIB_BUILD_CMDS
 endef
 
 define ZLIB_INSTALL_STAGING_CMDS
-	$(MAKE1) -C $(@D) DESTDIR=$(STAGING_DIR) install
+	$(MAKE1) -C $(@D) DESTDIR=$(STAGING_DIR) LDCONFIG=true install
 endef
 
 define ZLIB_INSTALL_TARGET_CMDS
-	$(MAKE1) -C $(@D) DESTDIR=$(TARGET_DIR) install
+	$(MAKE1) -C $(@D) DESTDIR=$(TARGET_DIR) LDCONFIG=true install
 endef
 
 define HOST_ZLIB_INSTALL_CMDS
-	$(MAKE1) -C $(@D) install
+	$(MAKE1) -C $(@D) LDCONFIG=true install
 endef
 
 define ZLIB_CLEAN_CMDS