cmake4 (#88)

* cmake4

* cache

Author: teseoch

.github/workflows/continuous.yml

@@ -54,7 +54,7 @@ jobs:
 
       - name: Cache Build
         id: cache-build
-        uses: actions/cache@v4.0.2
+        uses: actions/cache@v4
         with:
           path: ${{ env.CACHE_PATH }}
           key: ${{ runner.os }}-${{ matrix.config }}-cache-${{ github.sha }}
@@ -106,7 +106,7 @@ jobs:
 
       - name: Cache build
         id: cache-build
-        uses: actions/cache@v4.0.2
+        uses: actions/cache@v4
         with:
           path: ${{ env.appdata }}\Mozilla\sccache
           key: ${{ runner.os }}-${{ matrix.config }}-cache-${{ github.sha }}

.github/workflows/coverage.yml

@@ -41,7 +41,7 @@ jobs:
 
       - name: Cache Build
         id: cache-build
-        uses: actions/cache@v4.0.2
+        uses: actions/cache@v4
         with:
           path: ${{ env.CACHE_PATH }}
           key: ${{ runner.os }}-Release-${{ matrix.threading }}-cache-${{ github.sha }}

CMakeLists.txt

@@ -10,6 +10,12 @@ endif()
 set(REQUIRED_CMAKE_VERSION "3.18.0")
 if(POLYSOLVE_TOPLEVEL_PROJECT)
     cmake_minimum_required(VERSION ${REQUIRED_CMAKE_VERSION})
+    SET(CMAKE_POLICY_VERSION_MINIMUM ${REQUIRED_CMAKE_VERSION})
+    if(CMAKE_VERSION VERSION_GREATER_EQUAL "4.0.0")
+        message(WARNING "CMake version is ${CMAKE_VERSION}, setting stuff for dependencies.")
+        SET(CMAKE_POLICY_VERSION_MINIMUM ${REQUIRED_CMAKE_VERSION})
+        set(POLYSOLVE_WITH_AMGCL OFF CACHE BOOL "Use AMGCL for solving linear systems")
+    endif()
 else()
     # Don't use cmake_minimum_required here to avoid implicitly overriding parent policies
     if(${CMAKE_VERSION} VERSION_LESS ${REQUIRED_CMAKE_VERSION})