fix: universal2 build (#90)

ExternalProject_add does not forward CMAKE_OSX_ARCHITECTURES to the external project. This leads to a broken universal2 build which only has the x86_64 binary.
Let's forward a few variables to the external project to fix this.

CMakeLists.txt

@@ -102,6 +102,30 @@ if(UNIX AND NOT APPLE)
     )
 else()
   set(Ninja_BINARY_DIR ${CMAKE_BINARY_DIR}/Ninja-build)
+  # cache arguments
+  set(_cache_args )
+  foreach(var_name IN ITEMS
+    CMAKE_BUILD_TYPE
+    CMAKE_TOOLCHAIN_FILE
+    CMAKE_BUILD_PARALLEL_LEVEL
+    CMAKE_JOB_POOLS
+    CMAKE_JOB_POOL_COMPILE
+    CMAKE_JOB_POOL_LINK
+    CMAKE_OSX_DEPLOYMENT_TARGET
+    CMAKE_OSX_ARCHITECTURES
+    CMAKE_OSX_SYSROOT
+    )
+    if(DEFINED ${var_name})
+      list(APPEND _cache_args
+        -D${var_name}:STRING=${${var_name}}
+        )
+      message(STATUS "SuperBuild - ${var_name}: ${${var_name}}")
+    endif()
+  endforeach()
+  # _cache_args should not be empty
+  list(APPEND _cache_args
+    -DNINJA_SUPERBUILD:BOOL=true
+    )
   ExternalProject_add(build_ninja
     SOURCE_DIR ${Ninja_SOURCE_DIR}
     BINARY_DIR ${Ninja_BINARY_DIR}
@@ -111,6 +135,7 @@ else()
     USES_TERMINAL_CONFIGURE 1
     USES_TERMINAL_BUILD 1
     INSTALL_COMMAND ""
+    CMAKE_CACHE_ARGS ${_cache_args}
     DEPENDS
       download_ninja_source
     )

scripts/repair_wheel.py

@@ -5,6 +5,7 @@
 import subprocess
 import sys
 import tempfile
+import zipfile
 from pathlib import Path
 
 from convert_to_generic_platform_wheel import convert_to_generic_platform_wheel
@@ -58,6 +59,15 @@ def main():
         # we need to handle macOS x86_64 & arm64 here for now, let's use additional_platforms for this.
         additional_platforms = []
         if os_ == "macos":
+            # delocate-wheel --require-archs does not seem to check executables...
+            with tempfile.TemporaryDirectory() as tmpdir2_:
+                tmpdir2 = Path(tmpdir2_)
+                with zipfile.ZipFile(file, 'r') as zip_ref:
+                    zip_ref.extractall(tmpdir2)
+                exe = list(tmpdir2.glob("**/bin/ninja"))
+                assert len(exe) == 1, exe
+                subprocess.run(["lipo", str(exe[0]), "-verify_arch", "x86_64", "arm64"], check=True, stdout=subprocess.PIPE)
+
             # first, get the target macOS deployment target from the wheel
             match = re.match(r"^.*-macosx_(\d+)_(\d+)_.*\.whl$", file.name)
             assert match is not None, f"Couldn't match on {file.name}"