CMake: fix: add Zlib include directories when building with Zlib

This worked out before because everywhere we test has Zlib installed in the
default system paths. But technically this should be setup in order to correctly
use a Zlib installed somewhere else.

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8bd575510aaf2ce039479830f894606d99e36f35..b8a3dba8c51312cd188ee4df45528bed8ba3ad3a 100644 (file)
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Gradient URL references in SVG output once again align with their targets
   (linear or radial gradients) when `id` attributes are in use. This was
   arguably a regression in Graphviz 6.0.1. #2307
+- The CMake build system’s interactions with a Zlib installed in a non-system
+  location has been improved.
 
 ## [7.0.1] – 2022-11-09
 

diff --git a/lib/gvc/CMakeLists.txt b/lib/gvc/CMakeLists.txt
index b437bde8c8a734f401ef4b2ec7dc58a069b49610..90ba8b9015ef29e248a9a9b55f26bf9f9479d0ee 100644 (file)
--- a/lib/gvc/CMakeLists.txt
+++ b/lib/gvc/CMakeLists.txt
@@ -72,6 +72,7 @@ if(LTDL_FOUND)
 endif()
 
 if(ZLIB_FOUND)
+  target_include_directories(gvc SYSTEM PRIVATE ${ZLIB_INCLUDE_DIRS})
   target_link_libraries(gvc PUBLIC ${ZLIB_LIBRARIES})
 endif()