fix FFTW 3

Author: ChrisZYJ

toolchain/dependencies/CMakeLists.txt

@@ -32,10 +32,29 @@ if (MFC_FFTW)
         add_custom_target(fftw)
     else()
         if (NOT CMAKE_Fortran_COMPILER_ID STREQUAL "Cray")
+            message(STATUS "FFTW: Preparing to configure with CMake 4.0 compatibility fix")
+            
+            # Patch FFTW CMakeLists.txt
+            file(WRITE "${CMAKE_BINARY_DIR}/patch_fftw.cmake" 
+                 "file(READ \"\${SOURCE_DIR}/CMakeLists.txt\" content)
+                  string(REPLACE \"cmake_minimum_required(VERSION 2.8\" \"cmake_minimum_required(VERSION 3.5\" content \"\${content}\")
+                  file(WRITE \"\${SOURCE_DIR}/CMakeLists.txt\" \"\${content}\")
+                  message(STATUS \"FFTW: CMakeLists.txt patched to require CMake 3.5+\")")
+            
             ExternalProject_Add(fftw
                 URL        "http://www.fftw.org/fftw-3.3.10.tar.gz"
+                # More debugging info
+                LOG_DOWNLOAD    ON
+                LOG_UPDATE      ON
+                LOG_CONFIGURE   ON
+                LOG_BUILD       ON
+                LOG_INSTALL     ON
+                LOG_PATCH       ON
+                # Add this to patch the CMakeLists file before configure
+                PATCH_COMMAND   ${CMAKE_COMMAND} -DSOURCE_DIR=<SOURCE_DIR> -P ${CMAKE_BINARY_DIR}/patch_fftw.cmake
                 CMAKE_ARGS -DBUILD_TESTS=OFF
                            -DBUILD_SHARED_LIBS=OFF
+                           # Not enough to fix the issue, but we'll keep it
                            -DCMAKE_POLICY_VERSION_MINIMUM=3.5
                            "-DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}"
             )

toolchain/patches/fftw-cmake-fix.patch

@@ -0,0 +1,7 @@
+--- CMakeLists.txt.orig
++++ CMakeLists.txt
+@@ -1,4 +1,4 @@
+-cmake_minimum_required(VERSION 2.8.0)
++cmake_minimum_required(VERSION 3.5)
+ 
+ project(fftw)