Only include zlib directory when building the exiv2lib

cmake/findDependencies.cmake

@@ -12,7 +12,6 @@ find_package(Threads REQUIRED)
 
 if( EXIV2_ENABLE_PNG )
     find_package( ZLIB REQUIRED )
-    include_directories( ${ZLIB_INCLUDE_DIR} )
 endif( )
 
 if( EXIV2_ENABLE_WEBREADY )

src/CMakeLists.txt

@@ -224,6 +224,9 @@ if ( UNIX AND CMAKE_SYSTEM_NAME STREQUAL "FreeBSD" )
     set (FREEBSD 1)
 endif()
 
+target_include_directories(exiv2lib_int PRIVATE ${ZLIB_INCLUDE_DIR})
+target_include_directories(exiv2lib PRIVATE ${ZLIB_INCLUDE_DIR})
+
 if (EXIV2_ENABLE_XMP)
     #target_include_directories(exiv2lib PRIVATE ${CMAKE_SOURCE_DIR}/xmpsdk/include)
     target_link_libraries(exiv2lib PUBLIC xmp)