Keep WITH_SYSTEM_ZLIB (but added deprecation notice).

Keep HAVE_ZLIB - added config include to opennurbs_zlib.cpp.
Correctly check for ZLIB for libpng_wrapper as it includes <zlib.h>

Author: larshg

CMakeLists.txt

@@ -449,6 +449,14 @@ endif()
 # Boost (required)
 include("${PCL_SOURCE_DIR}/cmake/pcl_find_boost.cmake")
 
+# System zlib (for io-png and nurbs on surface)
+option(WITH_SYSTEM_ZLIB "Use system zlib" TRUE)
+message(WARNING "WITH_SYSTEM_ZLIB option is deprecated, has no effect and will be removed in 1.18.")
+find_package(ZLIB)
+if(ZLIB_FOUND)
+  set(HAVE_ZLIB ON)
+endif()
+
 option(WITH_SYSTEM_CJSON "Use system cJSON" TRUE)
 if(WITH_SYSTEM_CJSON)
   find_package(cJSON)

io/CMakeLists.txt

@@ -5,9 +5,9 @@ set(SUBSYS_EXT_DEPS boost eigen3)
 
 PCL_SUBSYS_OPTION(build "${SUBSYS_NAME}" "${SUBSYS_DESC}" ON)
 if(WIN32)
-  PCL_SUBSYS_DEPEND(build NAME ${SUBSYS_NAME} DEPS ${SUBSYS_DEPS} OPT_DEPS openni openni2 ensenso davidSDK dssdk rssdk rssdk2 pcap png vtk OpenMP EXT_DEPS ${SUBSYS_EXT_DEPS})
+  PCL_SUBSYS_DEPEND(build NAME ${SUBSYS_NAME} DEPS ${SUBSYS_DEPS} OPT_DEPS openni openni2 ensenso davidSDK dssdk rssdk rssdk2 pcap png vtk OpenMP ZLIB EXT_DEPS ${SUBSYS_EXT_DEPS})
 else()
-  PCL_SUBSYS_DEPEND(build NAME ${SUBSYS_NAME} DEPS ${SUBSYS_DEPS} OPT_DEPS openni openni2 ensenso davidSDK dssdk pcap png vtk libusb OpenMP EXT_DEPS ${SUBSYS_EXT_DEPS})
+  PCL_SUBSYS_DEPEND(build NAME ${SUBSYS_NAME} DEPS ${SUBSYS_DEPS} OPT_DEPS openni openni2 ensenso davidSDK dssdk pcap png vtk libusb OpenMP ZLIB EXT_DEPS ${SUBSYS_EXT_DEPS})
 endif()
 
 PCL_ADD_DOC("${SUBSYS_NAME}")
@@ -244,7 +244,7 @@ set(srcs
   ${RSSDK2_GRABBER_SOURCES}
 )
 
-if(PNG_FOUND)
+if(PNG_FOUND AND ZLIB_FOUND)
   list(APPEND srcs
     src/libpng_wrapper.cpp
   )
@@ -373,6 +373,10 @@ if(PNG_FOUND)
   target_link_libraries("${LIB_NAME}" ${PNG_LIBRARIES})
 endif()
 
+if(PNG_FOUND AND ZLIB_FOUND)
+  target_link_libraries("${LIB_NAME}" ZLIB::ZLIB)
+endif()
+
 if(LIBUSB_FOUND)
   target_link_libraries("${LIB_NAME}" libusb::libusb)
 endif()

pcl_config.h.in

@@ -63,6 +63,8 @@
 
 #cmakedefine HAVE_PNG
 
+#cmakedefine HAVE_ZLIB
+
 #cmakedefine HAVE_CJSON
 
 #cmakedefine PCL_PREFER_BOOST_FILESYSTEM

surface/CMakeLists.txt

@@ -68,8 +68,8 @@ if(BUILD_surface_on_nurbs)
   include(src/on_nurbs/on_nurbs.cmake)
 
   find_package(ZLIB REQUIRED)
-  list(APPEND ON_NURBS_LIBRARIES ${ZLIB_LIBRARIES})
   list(APPEND SUBSYS_EXT_DEPS zlib)
+  list(APPEND ON_NURBS_LIBRARIES ZLIB::ZLIB)
 endif()
 
 set(POISSON_INCLUDES

surface/src/3rdparty/opennurbs/opennurbs_zlib.cpp

@@ -14,6 +14,7 @@
 ////////////////////////////////////////////////////////////////
 */
 
+#include <pcl/pcl_config.h> // for HAVE_ZLIB
 #include "pcl/surface/3rdparty/opennurbs/opennurbs.h"
 
 bool ON_BinaryArchive::WriteCompressedBuffer(