CMake: Fix builds without zstd

Only use zstd defined variables if zstd was found.

1 files changed, 2 insertions, 2 deletions

diff --git a/apt-pkg/CMakeLists.txt b/apt-pkg/CMakeLists.txt
index fdf27f92d..64709ce34 100644
--- a/apt-pkg/CMakeLists.txt
+++ b/apt-pkg/CMakeLists.txt
@@ -44,7 +44,7 @@ target_include_directories(apt-pkg
                                    ${BZIP2_INCLUDE_DIR}
                                    ${LZMA_INCLUDE_DIRS}
                                    ${LZ4_INCLUDE_DIRS}
-                                   ${ZSTD_INCLUDE_DIRS}
+                                   $<$<BOOL:${ZSTD_FOUND}>:${ZSTD_INCLUDE_DIRS}>
                                    $<$<BOOL:${UDEV_FOUND}>:${UDEV_INCLUDE_DIRS}>
                                    ${ICONV_INCLUDE_DIRS}
 )
@@ -56,7 +56,7 @@ target_link_libraries(apt-pkg
                              ${BZIP2_LIBRARIES}
                              ${LZMA_LIBRARIES}
                              ${LZ4_LIBRARIES}
-                             ${ZSTD_LIBRARIES}
+                             $<$<BOOL:${ZSTD_FOUND}>:${ZSTD_LIBRARIES}>
                              $<$<BOOL:${UDEV_FOUND}>:${UDEV_LIBRARIES}>
                              ${ICONV_LIBRARIES}
 )