Use FetchContent instead

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.10)
+cmake_minimum_required(VERSION 3.11)
 
 project(flat_map LANGUAGES CXX)
 set(CMAKE_CXX_STANDARD 17)

bench/CMakeLists.txt

@@ -1,13 +1,13 @@
 include(${PROJECT_SOURCE_DIR}/cmake/benchmark.cmake)
 
-add_custom_target(benchmark)
-set_target_properties(benchmark PROPERTIES EXCLUDE_FROM_ALL 1 EXCLUDE_FROM_DEFAULT_BUILD 1)
+add_custom_target(bench)
+set_target_properties(bench PROPERTIES EXCLUDE_FROM_ALL 1 EXCLUDE_FROM_DEFAULT_BUILD 1)
 
 macro(add_bench benchname)
   add_benchmark(${benchname} ${ARGN})
   set_target_properties(${benchname} PROPERTIES EXCLUDE_FROM_ALL 1 EXCLUDE_FROM_DEFAULT_BUILD 1)
   target_link_libraries(${benchname} flat_map)
-  add_dependencies(benchmark ${benchname})
+  add_dependencies(bench ${benchname})
 endmacro()
 
 add_bench(map_construction map_construction.cpp)

cmake/benchmark.cmake

@@ -1,29 +1,19 @@
 find_package(benchmark QUIET)
 
-if(benchmark_FOUND)
-  add_library(benchmarkLib ALIAS benchmark::benchmark)
-  add_library(benchmarkInc ALIAS benchmark::benchmark)
-else()
-  include(ExternalProject)
+if(NOT benchmark_FOUND)
+  include(FetchContent)
 
-  ExternalProject_Add(
-    benchmarkBuild
+  set(BENCHMARK_ENABLE_TESTING Off)
+  FetchContent_Declare(
+    benchmark
     GIT_REPOSITORY https://github.com/google/benchmark
-    GIT_TAG v1.5.5
-    PREFIX external
-    CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=${CMAKE_BINARY_DIR}/external
-               -DCMAKE_BUILD_TYPE=Release
-               -DBENCHMARK_ENABLE_TESTING=Off
+    GIT_TAG v1.8.4
   )
 
-  add_library(benchmarkLib STATIC IMPORTED)
-  set_target_properties(benchmarkLib PROPERTIES IMPORTED_LOCATION ${CMAKE_BINARY_DIR}/external/lib/libbenchmark.a)
-  add_library(benchmarkInc INTERFACE)
-  target_include_directories(benchmarkInc INTERFACE ${CMAKE_BINARY_DIR}/external/include)
-  add_dependencies(benchmarkInc benchmarkBuild)
+  FetchContent_MakeAvailable(benchmark)
 endif()
 
 function(add_benchmark benchname)
   add_executable(${benchname} ${ARGN})
-  target_link_libraries(${benchname} benchmarkInc benchmarkLib)
+  target_link_libraries(${benchname} benchmark::benchmark)
 endfunction()