CMake adjustments (apple#69)

* build: update cmake for TestHelpers rename

* build: make CMake build on macOS work

Unfortunately, XCTest importing is not working for some reason
currently.  However, this allows you to build on Darwin as follows:

```
cmake -G Ninja -D CMAKE_BUILD_TYPE=Release -D BUILD_TESTING=NO -S . -B out
ninja -C out
```

Windows and Linux builds remain functional.

* build: refactor Examples build with CMake

Although this goes contrary to best practices for CMake, this helps keep
the source tree a bit leaner for the Examples.

Author: compnerd

Examples/CMakeLists.txt

@@ -1,3 +1,15 @@
-add_subdirectory(math)
-add_subdirectory(repeat)
-add_subdirectory(roll)
+add_executable(math
+  math/main.swift)
+target_link_libraries(math PRIVATE
+  ArgumentParser)
+
+add_executable(repeat
+  repeat/main.swift)
+target_link_libraries(repeat PRIVATE
+  ArgumentParser)
+
+add_executable(roll
+  roll/main.swift
+  roll/SplitMix64.swift)
+target_link_libraries(roll PRIVATE
+  ArgumentParser)

Examples/math/CMakeLists.txt

@@ -36,4 +36,4 @@ set_target_properties(ArgumentParser PROPERTIES
 target_compile_options(ArgumentParser PRIVATE
   $<$<BOOL:${BUILD_TESTING}>:-enable-testing>)
 target_link_libraries(ArgumentParser PRIVATE
-  Foundation)
+  $<$<NOT:$<PLATFORM_ID:Darwin>>:Foundation>)

Examples/repeat/CMakeLists.txt

@@ -1,4 +1,4 @@
 add_subdirectory(ArgumentParser)
 if(BUILD_TESTING)
-  add_subdirectory(TestHelpers)
+  add_subdirectory(SAPTestHelpers)
 endif()

Examples/roll/CMakeLists.txt

@@ -1,8 +1,8 @@
-add_library(TestHelpers
+add_library(SAPTestHelpers
   StringHelpers.swift
   TestHelpers.swift)
-set_target_properties(TestHelpers PROPERTIES
+set_target_properties(SAPTestHelpers PROPERTIES
   INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_Swift_MODULE_DIRECTORY})
-target_link_libraries(TestHelpers PUBLIC
+target_link_libraries(SAPTestHelpers PUBLIC
   ArgumentParser
   XCTest)

Sources/ArgumentParser/CMakeLists.txt

@@ -16,4 +16,4 @@ add_library(EndToEndTests
   SubcommandEndToEndTests.swift
   ValidationEndToEndTests.swift)
 target_link_libraries(EndToEndTests PUBLIC
-  TestHelpers)
+  SAPTestHelpers)

Sources/CMakeLists.txt

@@ -8,4 +8,4 @@ add_library(UnitTests
   UsageGenerationTests.swift)
 target_link_libraries(UnitTests PRIVATE
   ArgumentParser
-  TestHelpers)
+  SAPTestHelpers)