Zip: Allow usage of system zlib (default if found)

Set QTC_USE_SYSTEM_ZLIB to override the default
(which is already done for our prebuilt binaries in build.py)

Fixes: QTCREATORBUG-32584
Change-Id: Ib893ee9daa24a831308dfffd6e33d6e79aac2356
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/libs/solutions/zip/CMakeLists.txt

@@ -6,42 +6,57 @@ add_qtc_library(Zip
     zipreader.h
     zipwriter.h
     zip_global.h
+)
+
+find_package(ZLIB QUIET)
+if(ZLIB_FOUND)
+  set(QTC_USE_SYSTEM_ZLIB_DEFAULT ON)
+else()
+  set(QTC_USE_SYSTEM_ZLIB_DEFAULT OFF)
+endif()
+option(QTC_USE_SYSTEM_ZLIB "Use system zlib for Zip" ${QTC_USE_SYSTEM_ZLIB_DEFAULT})
+
+if (QTC_USE_SYSTEM_ZLIB)
+  extend_qtc_library(Zip
+    FEATURE_INFO "System zlib"
+    DEPENDS ZLIB::ZLIB
+  )
+else()
+  extend_qtc_library(Zip
+    FEATURE_INFO "Integrated zlib"
+    SOURCES_PREFIX ${CMAKE_CURRENT_LIST_DIR}/../../3rdparty/zlib/src
     INCLUDES
       ${CMAKE_CURRENT_LIST_DIR}/../../3rdparty/zlib/src
-)
-
-extend_qtc_library(Zip
-  SOURCES_PREFIX ${CMAKE_CURRENT_LIST_DIR}/../../3rdparty/zlib/src
-  SKIP_AUTOMOC
-  SOURCES
-    adler32.c
-    compress.c
-    crc32.c
-    crc32.h
-    deflate.c
-    deflate.h
-    gzclose.c
-    gzguts.h
-    gzlib.c
-    gzread.c
-    gzwrite.c
-    infback.c
-    inffast.c
-    inffast.h
-    inffixed.h
-    inflate.c
-    inflate.h
-    inftrees.c
-    inftrees.h
-    trees.c
-    trees.h
-    uncompr.c
-    zconf.h
-    zlib.h
-    zutil.c
-    zutil.h
-)
-
-if(MSVC)
-  target_compile_options(Zip PUBLIC /wd4996)
+    SKIP_AUTOMOC
+    SOURCES
+      adler32.c
+      compress.c
+      crc32.c
+      crc32.h
+      deflate.c
+      deflate.h
+      gzclose.c
+      gzguts.h
+      gzlib.c
+      gzread.c
+      gzwrite.c
+      infback.c
+      inffast.c
+      inffast.h
+      inffixed.h
+      inflate.c
+      inflate.h
+      inftrees.c
+      inftrees.h
+      trees.c
+      trees.h
+      uncompr.c
+      zconf.h
+      zlib.h
+      zutil.c
+      zutil.h
+  )
+  if(MSVC)
+    target_compile_options(Zip PUBLIC /wd4996)
+  endif()
 endif()