Replace usage of "@bazel_tools//tools/cpp:current_cc_toolchain" with "@build_bazel_rules_apple//apple:default_cc_toolchain_forwarder"
Rename _toolchain to _mac_toolchain, this matches rules_apple and better represents that the toolchain is for the host platform
Add cfg = "exec" to the mac and xplat toolchains
This is required to fix toolchain resolution errors on Bazel 7. These toolchains are for the host and so exec is correct here. This is the same cfg they use in rules_apple
Prepares our mac and xplat toolchains for Bazel 7
Changes:
"@bazel_tools//tools/cpp:current_cc_toolchain"with"@build_bazel_rules_apple//apple:default_cc_toolchain_forwarder"_toolchainto_mac_toolchain, this matches rules_apple and better represents that the toolchain is for the host platformcfg = "exec"to the mac and xplat toolchainsexecis correct here. This is the same cfg they use in rules_apple