Retry gRPC CMake configuration if it fails

The gRPC CMake configuration step can fail to due to a failure when downloading third party archives.  These failures are expected, and the user is instructed to retry.  So, if configuration fails, retry it

Also set the `gRPC_DOWNLOAD_ARCHIVES` CMake flag to `False`, to avoid downloading these unnecessary archives in the first place, in versions of gRPC that understand the flag

recipes/grpc/all/conanfile.py

@@ -1,7 +1,7 @@
 import os
 
 from conan import ConanFile
-from conan.errors import ConanInvalidConfiguration
+from conan.errors import ConanInvalidConfiguration, ConanException
 from conan.tools.apple import is_apple_os
 from conan.tools.build import cross_building, valid_min_cppstd, check_min_cppstd
 from conan.tools.cmake import cmake_layout, CMake, CMakeToolchain, CMakeDeps
@@ -174,6 +174,11 @@ def generate(self):
         tc.cache_variables["gRPC_BUILD_GRPC_PYTHON_PLUGIN"] = self.options.python_plugin
         tc.cache_variables["gRPC_BUILD_GRPC_RUBY_PLUGIN"] = self.options.ruby_plugin
 
+        # Never download unnecessary archives
+        # (supported in gRPC >= 1.62.0)
+        tc.cache_variables["gRPC_DOWNLOAD_ARCHIVES"] = False
+
+
         # Consumed targets (abseil) via interface target_compiler_feature can propagate newer standards
         if not valid_min_cppstd(self, self._cxxstd_required):
             tc.cache_variables["CMAKE_CXX_STANDARD"] = self._cxxstd_required
@@ -207,7 +212,13 @@ def _patch_sources(self):
     def build(self):
         self._patch_sources()
         cmake = CMake(self)
-        cmake.configure()
+
+        # The CMake configure step can fail spuriously, but succeed on a retry
+        try:
+            cmake.configure()
+        except ConanException:
+            cmake.configure()
+
         cmake.build()
 
     def package(self):