From caf561457d09a942bf0789f3e7ebc3870714a65f Mon Sep 17 00:00:00 2001
From: Rangi <35663410+Rangi42@users.noreply.github.com>
Date: Wed, 24 Jun 2026 17:53:11 -0400
Subject: [PATCH] Warn about CMake <3.27 for Windows-targeted builds (#1989)

We only use `$<INSTALL_PREFIX>`` when cross-compiling for MinGW on Linux,
so the relevant block is now wrapped in `if(WIN32)`
so a user can more easily lower the `cmake_minimum_required` version.
---
 src/CMakeLists.txt | 62 +++++++++++++++++++++++++---------------------
 1 file changed, 34 insertions(+), 28 deletions(-)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 0c808877..a55713ef 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -118,32 +118,38 @@ add_custom_command(TARGET rgbgfx POST_BUILD COMMENT "Copying rgbgfx's DLLs"
                    COMMAND ${CMAKE_COMMAND} -E copy -t $<TARGET_FILE_DIR:rgbgfx> $<TARGET_RUNTIME_DLLS:rgbgfx>
                    COMMAND_EXPAND_LISTS VERBATIM)
 
-# On Windows, you don't link against DLLs directly, but against an import library for that DLL.
-# This leads to, sometimes, the DLL being stored in a directory far away from the import library itself!
-set(DLL_SEARCH_DIRS CACHE PATH "List of directories in which DLLs will be searched")
-cmake_path(CONVERT "${DLL_SEARCH_DIRS}" TO_CMAKE_PATH_LIST search_dirs NORMALIZE)
-# TODO: we've only tested this with MinGW, but it may not work with other uses of the variable.
-#       Anyone who knows how to handle this better, feel free to submit a patch!
-if(DEFINED CMAKE_FIND_ROOT_PATH)
-  list(APPEND search_dirs "${CMAKE_FIND_ROOT_PATH}/bin")
+if(WIN32)
+  # CMake 3.27 is required for `$<INSTALL_PREFIX>`, but is only needed when cross-compiling for MinGW.
+  if(CMAKE_VERSION VERSION_LESS "3.27")
+    message(WARNING "CMake 3.27 or higher is required for `\$<INSTALL_PREFIX>` inside `install(CODE)`")
+  endif()
+  # On Windows, you don't link against DLLs directly, but against an import library for that DLL.
+  # This leads to, sometimes, the DLL being stored in a directory far away from the import library itself!
+  set(DLL_SEARCH_DIRS CACHE PATH "List of directories in which DLLs will be searched")
+  cmake_path(CONVERT "${DLL_SEARCH_DIRS}" TO_CMAKE_PATH_LIST search_dirs NORMALIZE)
+  # TODO: we've only tested this with MinGW, but it may not work with other uses of the variable.
+  #       Anyone who knows how to handle this better, feel free to submit a patch!
+  if(DEFINED CMAKE_FIND_ROOT_PATH)
+    list(APPEND search_dirs "${CMAKE_FIND_ROOT_PATH}/bin")
+  endif()
+  # Escape the search paths in a form that makes them suitable for splatting into the CMake install script.
+  list(TRANSFORM search_dirs REPLACE "([\\$\"])" "\\\\1") # Neutralize escapes and variable refs...
+  list(TRANSFORM search_dirs REPLACE "^(.+)\$" "\"\\1\"") # ...and quote each argument.
+  list(JOIN search_dirs " " search_dirs_splat)
+  # This is a modified version of the install code generated by
+  # `install(TARGETS rgbgfx RUNTIME_DEPENDENCIES)`.
+  # Unfortunately, that `install(TARGETS)` is outright not supported when cross-compiling,
+  # and working around that has CMake fail to resolve the DLL locations with MinGW,
+  # due to not specifying any `DIRECTORIES` and the system search path being ineffective.
+  install(CODE "\
+  file(GET_RUNTIME_DEPENDENCIES
+      RESOLVED_DEPENDENCIES_VAR rgbgfx_deps
+      EXECUTABLES \"$<TARGET_FILE:rgbgfx>\"
+      DIRECTORIES ${search_dirs_splat} \"$<TARGET_FILE_DIR:ZLIB::ZLIB>\" \"$<TARGET_FILE_DIR:PNG::PNG>\"
+      PRE_EXCLUDE_REGEXES \"^kernel32\\\\.dll$\" \"^msvcrt.?.?\\\\.dll\" \"^api-ms-win-.*\\\\.dll$\")
+    foreach(rgbgfx_dep IN LISTS rgbgfx_deps)
+      file(INSTALL DESTINATION \"$<INSTALL_PREFIX>/${CMAKE_INSTALL_BINDIR}\" TYPE SHARED_LIBRARY FILES \${rgbgfx_dep}
+        FOLLOW_SYMLINK_CHAIN)
+    endforeach()"
+          COMPONENT shared-libs EXCLUDE_FROM_ALL) # Most platforms install those separately.
 endif()
-# Escape the search paths in a form that makes them suitable for splatting into the CMake install script.
-list(TRANSFORM search_dirs REPLACE "([\\$\"])" "\\\\1") # Neutralize escapes and variable refs...
-list(TRANSFORM search_dirs REPLACE "^(.+)\$" "\"\\1\"") # ...and quote each argument.
-list(JOIN search_dirs " " search_dirs_splat)
-# This is a modified version of the install code generated by
-# `install(TARGETS rgbgfx RUNTIME_DEPENDENCIES)`.
-# Unfortunately, that `install(TARGETS)` is outright not supported when cross-compiling,
-# and working around that has CMake fail to resolve the DLL locations with MinGW,
-# due to not specifying any `DIRECTORIES` and the system search path being ineffective.
-install(CODE "\
-file(GET_RUNTIME_DEPENDENCIES
-    RESOLVED_DEPENDENCIES_VAR rgbgfx_deps
-    EXECUTABLES \"$<TARGET_FILE:rgbgfx>\"
-    DIRECTORIES ${search_dirs_splat} \"$<TARGET_FILE_DIR:ZLIB::ZLIB>\" \"$<TARGET_FILE_DIR:PNG::PNG>\"
-    PRE_EXCLUDE_REGEXES \"^kernel32\\\\.dll$\" \"^msvcrt.?.?\\\\.dll\" \"^api-ms-win-.*\\\\.dll$\")
-  foreach(rgbgfx_dep IN LISTS rgbgfx_deps)
-    file(INSTALL DESTINATION \"$<INSTALL_PREFIX>/${CMAKE_INSTALL_BINDIR}\" TYPE SHARED_LIBRARY FILES \${rgbgfx_dep}
-      FOLLOW_SYMLINK_CHAIN)
-  endforeach()"
-        COMPONENT shared-libs EXCLUDE_FROM_ALL) # Most platforms install those separately.