SDL_image: cmake: don't wrap ZLIB_INCLUDE_DIR with BUILD_INTERFACE genex (6baaa)

From 6baaa342334a5058737c7fdaa022bbe0a3987626 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Tue, 23 May 2023 15:45:12 +0200
Subject: [PATCH] cmake: don't wrap ZLIB_INCLUDE_DIR with BUILD_INTERFACE genex

When libpng is configured with awk available, the ZLIB_INCLUDE_DIR
variable is copied and used in a cmake script.
There, it is used as an argument to the C compiler.
Because script mode does not have a generator phase, don't use genex
variables here.
---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e9449a67..c0000ea0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -333,7 +333,7 @@ if(SDL3IMAGE_ZLIB)
         # PNG_BUILD_ZLIB variable is used by vendored libpng
         set(PNG_BUILD_ZLIB ON CACHE BOOL "libpng option to tell it should use 'our' vendored ZLIB library" FORCE)
         # ZLIB_INCLUDE_DIR variable is used by vendored libpng
-        set(ZLIB_INCLUDE_DIR "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/external/zlib;${CMAKE_CURRENT_BINARY_DIR}/external/zlib>" CACHE STRING "path of zlib, passed to libpng" FORCE)
+        set(ZLIB_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/external/zlib;${CMAKE_CURRENT_BINARY_DIR}/external/zlib" CACHE STRING "path of zlib, passed to libpng" FORCE)
         # ZLIB_LIBRARY variable is used by vendored libpng
         if(SDL3IMAGE_ZLIB_SHARED)
             set(ZLIB_LIBRARY zlib)