Workaround to keep old cmake versions limping around.

indra/CMakeLists.txt

@@ -7,6 +7,9 @@
 ## 3.13/12 is needed for add_link_options/add_compile_definitions
 ## 3.14 added FILE CREATE_LINK
 ## 3.16 is needed for target_precompile_headers
+## Nicky: Ideally we want at least 3.21 for good preset support
+##   We're not there yet, but once done, there is a kludge in Linking.cmake
+#    "if(${CMAKE_VERSION} VERSION_LESS "3.20.0")" that can also be removed
 cmake_minimum_required(VERSION 3.16.0 FATAL_ERROR)
 
 set(ROOT_PROJECT_NAME "SecondLife" CACHE STRING

indra/cmake/Linking.cmake

@@ -8,7 +8,15 @@ set(ARCH_PREBUILT_DIRS_PLUGINS ${AUTOBUILD_INSTALL_DIR}/plugins)
 set(ARCH_PREBUILT_DIRS_RELEASE ${AUTOBUILD_INSTALL_DIR}/lib/release)
 set(ARCH_PREBUILT_DIRS_DEBUG ${AUTOBUILD_INSTALL_DIR}/lib/debug)
 if (WINDOWS OR DARWIN )
-  set(SHARED_LIB_STAGING_DIR ${CMAKE_BINARY_DIR}/sharedlibs/$<IF:$<BOOL:${LL_GENERATOR_IS_MULTI_CONFIG}>,$<CONFIG>,>)
+  # Kludge for older cmake versions, 3.20+ is needed to use a genex in add_custom_command( OUTPUT <var> ... )
+  # Using this will work okay-ish, as Debug is not supported anyway. But for property multi config and also
+  # ninja support the genex version is preferred.
+  if(${CMAKE_VERSION} VERSION_LESS "3.20.0")
+    set(SHARED_LIB_STAGING_DIR ${CMAKE_BINARY_DIR}/sharedlibs/Release)
+  else()
+    set(SHARED_LIB_STAGING_DIR ${CMAKE_BINARY_DIR}/sharedlibs/$<IF:$<BOOL:${LL_GENERATOR_IS_MULTI_CONFIG}>,$<CONFIG>,>)
+  endif()
+
   if( DARWIN )
     set( SHARED_LIB_STAGING_DIR ${SHARED_LIB_STAGING_DIR}/Resources)
   endif()