Add C++ flags to .bazelrc to build new abseil-cpp

abseil-cpp versions later after 20220623.1 require at least a C++14
compatible compiler to build. This, in turn, is required to build
protobuf version 22 and later. Bazel 7 is already compatible, but Bazel
6 requires these flags.

Author: mbland

.bazelrc

@@ -1,8 +1,24 @@
 build --enable_platform_specific_config
 
-#Windows needs --worker_quit_after_build due to workers not being shut down when the compiler tools need to be rebuilt (resulting in 'file in use' errors). See Bazel Issue#10498.
+# Needed to build versions of abseil-cpp newer than 20220624.1 under Bazel 6.
+# Can be removed after moving to Bazel 7. Borrowed from:
+# - https://github.com/bazelbuild/bazel/pull/20785
+#
+# At the same time, adding compiler flags like this does seem to make protobuf
+# recompile more often than it should. See:
+# - https://stackoverflow.com/questions/56880771/bazel-recompiles-protobuf-more-than-necessary
+# - https://github.com/bazelbuild/bazel/issues/7095
+build:linux --cxxopt=-std=c++17
+build:linux --host_cxxopt=-std=c++17
+build:macos --cxxopt=-std=c++17
+build:macos --host_cxxopt=-std=c++17
+build:windows --cxxopt=/std=c++17
+build:windows --host_cxxopt=/std=c++17
 
-build:windows --worker_quit_after_build --enable_runfiles 
+# Windows needs --worker_quit_after_build due to workers not being shut down
+# when the compiler tools need to be rebuilt (resulting in 'file in use'
+# errors). See Bazel Issue#10498.
+build:windows --worker_quit_after_build --enable_runfiles
 
 # Remove upon completing Bzlmod compatibility work.
 # - https://github.com/bazelbuild/rules_scala/issues/1482