fixup! CMake updates from @slurps-mad-rips

CMakeLists.txt

@@ -46,7 +46,7 @@ list(APPEND force-libcxx "CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME")
 list(APPEND build-docs "CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME")
 list(APPEND build-docs "NOT CMAKE_VERSION VERSION_LESS 3.11")
 list(APPEND build-docs "Doxygen_FOUND")
-list(APPEND build-docs "EXISTS docs")
+list(APPEND build-docs "EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/docs")
 
 option(CLI11_WARNINGS_AS_ERRORS "Turn all warnings into errors (for CI)")
 option(CLI11_SINGLE_FILE "Generate a single header file")
@@ -64,7 +64,7 @@ cmake_dependent_option(CLI11_BUILD_TESTS
 
 cmake_dependent_option(CLI11_BUILD_EXAMPLES
     "Build CLI11 examples" ON
-    "CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME;EXISTS examples" OFF)
+    "CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME;EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/examples" OFF)
 
 cmake_dependent_option(CLI11_BUILD_EXAMPLES_JSON
     "Build CLI11 json example" OFF
@@ -267,7 +267,7 @@ if(CLI11_BUILD_DOCS)
 endif()
 
 # From a build system, this might not be included.
-if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME AND EXISTS book)
+if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/book")
     add_subdirectory(book)
 endif()
 

examples/CMakeLists.txt

@@ -12,10 +12,12 @@ function(add_cli_exe T)
 endfunction()
 
 if(CLI11_BUILD_EXAMPLES_JSON)
+    message(STATUS "Using nlohmann/json")
     FetchContent_Declare(json
-        GIT_REPOSITORY https://github.com/nlohmann/json.git
-        GIT_SHALLOW 1
-        GIT_TAG v3.7.3)
+        URL https://github.com/nlohmann/json/releases/download/v3.7.3/include.zip
+        URL_HASH "SHA256=87b5884741427220d3a33df1363ae0e8b898099fbc59f1c451113f6732891014"
+    )
+
     FetchContent_GetProperties(json)
     if (NOT json_POPULATED)
         FetchContent_Populate(json)

tests/CMakeLists.txt

@@ -6,6 +6,7 @@ endif()
 list(APPEND CMAKE_MODULE_PATH "${CLI11_SOURCE_DIR}/cmake")
 
 if(CLI11_SANITIZERS)
+    message(STATUS "Using arsenm/sanitizers-cmake")
     FetchContent_Declare(sanitizers
         GIT_REPOSITORY https://github.com/arsenm/sanitizers-cmake.git
         GIT_SHALLOW 1