Tests: Add case covering non-writable CMAKE_BINARY_DIR

Issue: #24407

Tests/RunCMake/Configure/ReadOnly-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/Configure/ReadOnly-stderr.txt

@@ -0,0 +1,8 @@
+CMake Error: Unable to \(re\)create the private pkgRedirects directory:
+  [^
+]*/Tests/RunCMake/Configure/ReadOnly-build/CMakeFiles/pkgRedirects
+This may be caused by not having read/write access to the build directory.
+Try specifying a location with read/write access like:
+  cmake -B build
+If using a CMake presets file, ensure that preset parameter
+'binaryDir' expands to a writable directory.

Tests/RunCMake/Configure/ReadOnly.cmake

@@ -0,0 +1 @@
+message(FATAL_ERROR "This should not be reached!")

Tests/RunCMake/Configure/RunCMakeTest.cmake

@@ -55,3 +55,19 @@ if(NOT RunCMake_GENERATOR MATCHES "^Ninja Multi-Config$")
   run_cmake(NoCMAKE_DEFAULT_BUILD_TYPE)
   run_cmake(NoCMAKE_DEFAULT_CONFIGS)
 endif()
+
+if(NOT CMAKE_HOST_WIN32)
+  block()
+    # Test a non-writable build directory.
+    # Exclude when running as root because directories are always writable.
+    get_unix_uid(uid)
+    if(NOT uid STREQUAL "0")
+      set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/ReadOnly-build)
+      file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}")
+      file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
+      file(CHMOD "${RunCMake_TEST_BINARY_DIR}" PERMISSIONS OWNER_READ OWNER_EXECUTE GROUP_READ GROUP_EXECUTE WORLD_READ WORLD_EXECUTE)
+      set(RunCMake_TEST_NO_CLEAN 1)
+      run_cmake(ReadOnly)
+    endif()
+  endblock()
+endif()