Fix windows release builds (#26986)

* Don't try to build protobuf-src on windows

* Set protoc envar

.github/workflows/release-artifacts.yml

@@ -50,6 +50,7 @@ jobs:
           choco install openssl
           export OPENSSL_DIR="C:\Program Files\OpenSSL-Win64"
           choco install protoc
+          export PROTOC="C:\ProgramData\chocolatey\lib\protoc\tools\bin\protoc.exe"
           source /tmp/env.sh
           echo "::set-output name=tag::$CI_TAG"
           eval "$(ci/channel-info.sh)"

storage-bigtable/build-proto/Cargo.toml

@@ -12,5 +12,9 @@ version = "1.12.0"
 [workspace]
 
 [dependencies]
-protobuf-src = "1.0.5"
 tonic-build = "0.8.0"
+
+# windows users should install the protobuf compiler manually and set the PROTOC
+# envar to point to the installed binary
+[target."cfg(not(windows))".dependencies]
+protobuf-src = "1.0.5"

storage-bigtable/build-proto/src/main.rs

@@ -1,6 +1,7 @@
 fn main() -> Result<(), std::io::Error> {
     const PROTOC_ENVAR: &str = "PROTOC";
     if std::env::var(PROTOC_ENVAR).is_err() {
+        #[cfg(not(windows))]
         std::env::set_var(PROTOC_ENVAR, protobuf_src::protoc());
     }
 

storage-proto/Cargo.toml

@@ -29,5 +29,9 @@ name = "solana_storage_proto"
 targets = ["x86_64-unknown-linux-gnu"]
 
 [build-dependencies]
-protobuf-src = "1.0.5"
 tonic-build = "0.8.0"
+
+# windows users should install the protobuf compiler manually and set the PROTOC
+# envar to point to the installed binary
+[target."cfg(not(windows))".build-dependencies]
+protobuf-src = "1.0.5"

storage-proto/build.rs

@@ -1,6 +1,7 @@
 fn main() -> Result<(), std::io::Error> {
     const PROTOC_ENVAR: &str = "PROTOC";
     if std::env::var(PROTOC_ENVAR).is_err() {
+        #[cfg(not(windows))]
         std::env::set_var(PROTOC_ENVAR, protobuf_src::protoc());
     }