dcmtk: fix macOS build with host_arch=x86_64 & build_arch=arm64

Requires rosetta & `tools.build.cross_building:can_run=True`

recipes/dcmtk/all/conanfile.py

@@ -3,7 +3,7 @@
 
 from conan import ConanFile
 from conan.errors import ConanInvalidConfiguration
-from conan.tools.build import cross_building
+from conan.tools.build import can_run, cross_building
 from conan.tools.cmake import CMake, CMakeDeps, CMakeToolchain, cmake_layout
 from conan.tools.files import apply_conandata_patches, copy, export_conandata_patches, get, replace_in_file, rmdir, save
 from conan.tools.microsoft import is_msvc, is_msvc_static_runtime
@@ -118,12 +118,17 @@ def validate(self):
            self.settings.os == "Macos" and self.settings.arch == "armv8":
             # FIXME: Probable issue with flags, build includes header 'mmintrin.h'
             raise ConanInvalidConfiguration("Cross building to Macos M1 is not supported (yet)")
+        if hasattr(self, "settings_build") and cross_building(self) and \
+           self.settings.os == "Macos" and self.settings.arch == "x86_64" and not can_run(self):
+            raise ConanInvalidConfiguration("Cross building to macOS x86_64 is only supported from macOS arm64 using rosetta with 'tools.build.cross_building:can_run=True'")
 
     def source(self):
         get(self, **self.conan_data["sources"][self.version], strip_root=True)
 
     def generate(self):
         tc = CMakeToolchain(self)
+        if cross_building(self) and can_run(self):
+            tc.variables["CMAKE_CROSSCOMPILING_EMULATOR"] = ""
         # DICOM Data Dictionaries are required
         tc.variables["CMAKE_INSTALL_DATADIR"] = self._dcm_datadictionary_path.replace("\\", "/")
         tc.cache_variables["DCMTK_USE_FIND_PACKAGE"] = True
@@ -193,7 +198,12 @@ def _collect_cmake_required(self, host_dependency):
 
     def _patch_sources(self):
         apply_conandata_patches(self)
-
+        replace_in_file(
+            self,
+            os.path.join(self.source_folder, "CMake", "dcmtkTryRun.cmake"),
+            "if(CMAKE_CROSSCOMPILING)",
+            "if(CMAKE_CROSSCOMPILING AND NOT DEFINED CMAKE_CROSSCOMPILING_EMULATOR)",
+        )
         # Workaround for CMakeDeps bug with check_* like functions.
         # See https://github.com/conan-io/conan/issues/12012 & https://github.com/conan-io/conan/issues/12180
         if self.options.with_openssl: