add explicit branch for PROVIDER=none

cmake/benchmark.cmake

@@ -32,5 +32,6 @@ elseif(gRPC_BENCHMARK_PROVIDER STREQUAL "package")
     set(_gRPC_BENCHMARK_LIBRARIES benchmark::benchmark)
   endif()
   set(_gRPC_FIND_BENCHMARK "if(NOT benchmark_FOUND)\n  find_package(benchmark CONFIG)\nendif()")
+elseif(gRPC_BENCHMARK_PROVIDER STREQUAL "none")
+  # Benchmark is a test-only dependency and can be avoided if we're not building tests.
 endif()
-

cmake/gflags.cmake

@@ -29,5 +29,6 @@ elseif(gRPC_GFLAGS_PROVIDER STREQUAL "package")
     set(_gRPC_GFLAGS_LIBRARIES gflags::gflags)
   endif()
   set(_gRPC_FIND_GFLAGS "if(NOT gflags_FOUND)\n  find_package(gflags CONFIG)\nendif()")
+elseif(gRPC_GFLAGS_PROVIDER STREQUAL "none")
+  # gflags is a test-only dependency and can be avoided if we're not building tests.
 endif()
-