build: Pass --force_pic to bazel

We already pass the -fPIC option in envoy.bazelrc (build:linux
--copt=-fPIC) to the compiler, but bazel does not know about it and still
builds both .pic.o and .o objects. Passing --force_pic to bazel supresses
the .o compilation and saves build time.

Noticed when non-test sources (such as Compiling
source/common/network/address_impl.cc) were compiled for tests right
after cilium-envoy was built. With the --force_pic option the tests build
shows building only test files.

Signed-off-by: Jarno Rajahalme <jarno@isovalent.com>

Author: jrajahalme

.bazelrc

@@ -10,6 +10,10 @@ import %workspace%/envoy.bazelrc
 build --incompatible_enable_cc_toolchain_resolution
 build --platform_mappings=bazel/platform_mappings
 
+# envoy.bazelrc always sets -fPIC, tell bazel about it to suppress building both .o and .pic.o
+# objects from the same C++ sources.
+build --force_pic
+
 # Enable path normalization by default.
 # See: https://github.com/envoyproxy/envoy/pull/6519
 build --define path_normalization_by_default=true