make qt-freetype use qt-zlib when present

from the perspective of freetype, this looks like a system zlib.

Change-Id: Idb961850b2a92d456cfa2b027bdc85ce5e4be771
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

src/3rdparty/freetype/freetype.pro

@@ -64,10 +64,10 @@ win32 {
 INCLUDEPATH += $$PWD/include
 
 DEFINES += FT2_BUILD_LIBRARY
-contains(QT_CONFIG, system-zlib) {
-    DEFINES += FT_CONFIG_OPTION_SYSTEM_ZLIB
-    include($$PWD/../zlib_dependency.pri)
-}
+
+DEFINES += FT_CONFIG_OPTION_SYSTEM_ZLIB
+include(../zlib_dependency.pri)
+
 contains(QT_CONFIG, system-png) {
     DEFINES += FT_CONFIG_OPTION_USE_PNG
     include($$PWD/../png_dependency.pri)

src/src.pro

@@ -129,7 +129,12 @@ src_plugins.depends = src_sql src_xml src_network
 src_android.subdir = $$PWD/android
 
 # this order is important
-contains(QT_CONFIG, zlib)|cross_compile: SUBDIRS += src_qtzlib
+contains(QT_CONFIG, zlib)|cross_compile {
+    SUBDIRS += src_qtzlib
+    contains(QT_CONFIG, zlib) {
+        src_3rdparty_freetype.depends += src_corelib
+    }
+}
 SUBDIRS += src_tools_bootstrap src_tools_moc src_tools_rcc
 !contains(QT_DISABLED_FEATURES, regularexpression):pcre {
     SUBDIRS += src_3rdparty_pcre