package/open2300: fix static builds

Fixes http://autobuild.buildroot.org/results/036/036c9088cfaae421c15b650f35e7ffe6ab934031/

libmysqlclient needs -lz to build, so we have to pass it explicitly for
static builds.

For almost-two-and-a-half years this error has been happenning, noone
ever tried to fix it. This is now done, at last! ;-]

[Peter: add autobuilder reference]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/open2300/open2300.mk

@@ -21,6 +21,10 @@ OPEN2300_DEPENDENCIES += mysql
 OPEN2300_BINS += mysql2300 mysqlhistlog2300
 OPEN2300_CFLAGS += -I$(STAGING_DIR)/usr/include/mysql
 OPEN2300_LDFLAGS += -L$(STAGING_DIR)/usr/lib/mysql -lmysqlclient
+ifeq ($(BR2_STATIC_LIBS),y)
+# mysql needs -lz, so we need to specify it for static builds
+OPEN2300_LDFLAGS += -lz
+endif
 endif
 
 define OPEN2300_BUILD_CMDS