update envoy and fix build

[zirain]

fixes: #6111

[leosarra]

I'm having some issues in building envoy in Istio 1.25.1 after this commit (found via git bisect).

�[32mAnalyzing:�[0m target //:envoy (126 packages loaded, 774 targets configured)

�[32mINFO: �[0mRepository local_config_cc instantiated at:
  /DEFAULT.WORKSPACE.SUFFIX:181:13: in <toplevel>
  /tmp/home/.cache/bazel/_bazel_adpuser/ccbcef1e345c666ad54a8b240746f4c3/external/bazel_tools/tools/cpp/cc_configure.bzl:149:16: in cc_configure
Repository rule cc_autoconf defined at:
  /tmp/home/.cache/bazel/_bazel_adpuser/ccbcef1e345c666ad54a8b240746f4c3/external/bazel_tools/tools/cpp/cc_configure.bzl:109:30: in <toplevel>
�[31m�[1mERROR: �[0m/tmp/home/.cache/bazel/_bazel_adpuser/ccbcef1e345c666ad54a8b240746f4c3/external/bazel_tools/tools/cpp/lib_cc_configure.bzl:112:9: An error occurred during the fetch of repository 'local_config_cc':
   Traceback (most recent call last):
	File "/tmp/home/.cache/bazel/_bazel_adpuser/ccbcef1e345c666ad54a8b240746f4c3/external/bazel_tools/tools/cpp/cc_configure.bzl", line 91, column 33, in cc_autoconf_impl
		configure_unix_toolchain(repository_ctx, cpu_value, overriden_tools)
	File "/tmp/home/.cache/bazel/_bazel_adpuser/ccbcef1e345c666ad54a8b240746f4c3/external/bazel_tools/tools/cpp/unix_cc_configure.bzl", line 351, column 17, in configure_unix_toolchain
		cc = find_cc(repository_ctx, overriden_tools)
	File "/tmp/home/.cache/bazel/_bazel_adpuser/ccbcef1e345c666ad54a8b240746f4c3/external/bazel_tools/tools/cpp/unix_cc_configure.bzl", line 315, column 23, in find_cc
		cc = _find_generic(repository_ctx, "gcc", "CC", overriden_tools)
	File "/tmp/home/.cache/bazel/_bazel_adpuser/ccbcef1e345c666ad54a8b240746f4c3/external/bazel_tools/tools/cpp/unix_cc_configure.bzl", line 311, column 32, in _find_generic
		auto_configure_fail(msg)
	File "/tmp/home/.cache/bazel/_bazel_adpuser/ccbcef1e345c666ad54a8b240746f4c3/external/bazel_tools/tools/cpp/lib_cc_configure.bzl", line 112, column 9, in auto_configure_fail
		fail("\n%sAuto-Configuration Error:%s %s\n" % (red, no_color, msg))
Error in fail: 
�[0;31mAuto-Configuration Error:�[0m Cannot find gcc or CC (clang); either correct your path or set the CC environment variable
�[31m�[1mERROR: �[0mno such package '@@local_config_cc//': 
�[0;31mAuto-Configuration Error:�[0m Cannot find gcc or CC (clang); either correct your path or set the CC environment variable
�[31m�[1mERROR: �[0m/tmp/home/.cache/bazel/_bazel_adpuser/ccbcef1e345c666ad54a8b240746f4c3/external/bazel_tools/tools/cpp/BUILD:119:6: @@bazel_tools//tools/cpp:toolchain depends on @@local_config_cc//:toolchain in repository @@local_config_cc which failed to fetch. no such package '@@local_config_cc//': 
�[0;31mAuto-Configuration Error:�[0m Cannot find gcc or CC (clang); either correct your path or set the CC environment variable
�[31m�[1mERROR: �[0m/tmp/home/proxy/BUILD:41:16: errors encountered resolving select() keys for //:envoy
�[31m�[1mERROR: �[0mAnalysis of target '//:envoy' failed; build aborted
�[32mINFO: �[0mElapsed time: 23.060s, Critical Path: 0.56s
�[32mINFO: �[0m1 process: 1 internal.
�[31m�[1mERROR: �[0mBuild did NOT complete successfully

I suspect this is due to the LLVM path being hardcoded to "/usr/lib/llvm/bin" in build:linux --action_env=PATH=/usr/lib/llvm/bin:/usr/local/bin:/bin:/usr/bin.
This path is different from where I store my LLVM files. After updating the .bazelrc to match my LLVM path, it works fine.
Do you think the handling could be generalized so that the hardcoded path is no longer needed?

[zirain]

you can send a PR for it.