Upgrade rust/crates/grpcio-sys to 0.7.2

Test: make
Change-Id: Ic7521c73aacb4e68054f765ca1a2234e5511ee0e
diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
deleted file mode 100644
index 90abfbc..0000000
--- a/.cargo_vcs_info.json
+++ /dev/null
@@ -1,5 +0,0 @@
-{
-  "git": {
-    "sha1": "19a53b5cc9612511dabb365dae05286e807668e5"
-  }
-}
diff --git a/Android.bp b/Android.bp
index 88f71b4..f4e396b 100644
--- a/Android.bp
+++ b/Android.bp
@@ -74,14 +74,14 @@
 //   bindgen-0.51.1
 //   bitflags-1.2.1 "default"
 //   boringssl-src-0.1.0
-//   cc-1.0.63
+//   cc-1.0.66
 //   cexpr-0.3.6
 //   cfg-if-0.1.10
 //   clang-sys-0.28.1 "clang_6_0,gte_clang_3_6,gte_clang_3_7,gte_clang_3_8,gte_clang_3_9,gte_clang_4_0,gte_clang_5_0,gte_clang_6_0,libloading,runtime"
 //   cmake-0.1.45
 //   glob-0.3.0
 //   lazy_static-1.4.0
-//   libc-0.2.80 "default,std"
+//   libc-0.2.81 "default,std"
 //   libloading-0.5.2
 //   libz-sys-1.1.2 "default,libc,static,stock-zlib"
 //   memchr-2.3.4 "default,std,use_std"
diff --git a/Cargo.toml b/Cargo.toml
index 4068ea6..870630c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,7 +13,7 @@
 [package]
 edition = "2018"
 name = "grpcio-sys"
-version = "0.7.1"
+version = "0.7.2"
 authors = ["The TiKV Project Developers"]
 build = "build.rs"
 exclude = ["grpc/doc/*", "grpc/etc/*", "grpc/examples/*", "grpc/Makefile", "grpc/templates/*", "grpc/src/android/*", "grpc/src/csharp/*", "grpc/src/node/*", "grpc/src/objective-c/*", "grpc/src/php/*", "grpc/src/python/*", "grpc/src/ruby/*", "grpc/test/core/end2end/*", "grpc/third_party/zlib/*", "grpc/third_party/abseil-cpp/absl/time/internal/cctz/testdata", "grpc/third_party/benchmark/*", "grpc/third_party/bloaty/*", "grpc/third_party/boringssl-with-bazel/*", "grpc/third_party/libuv/*", "grpc/third_party/gflags/*", "grpc/third_party/googletest/*", "grpc/third_party/objective_c/*", "grpc/third_party/protobuf/*", "grpc/third_party/toolchans/*", "grpc/third_party/envoy-api/*", "grpc/third_party/googleapis/*", "grpc/third_party/protoc-gen-validate/*", "grpc/third_party/udpa/*", "grpc/tools/run_tests/generated/*", "grpc/test/core/", "!grpc/test/core/security/*.cc", "!grpc/test/core/util/cmdline.cc", "grpc/test/cpp"]
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
index 3071e0a..c6b816f 100644
--- a/Cargo.toml.orig
+++ b/Cargo.toml.orig
@@ -1,6 +1,6 @@
 [package]
 name = "grpcio-sys"
-version = "0.7.1"
+version = "0.7.2"
 authors = ["The TiKV Project Developers"]
 license = "Apache-2.0"
 keywords = ["grpc", "bindings"]
diff --git a/METADATA b/METADATA
index bea6ccc..bb80643 100644
--- a/METADATA
+++ b/METADATA
@@ -7,13 +7,13 @@
   }
   url {
     type: ARCHIVE
-    value: "https://static.crates.io/crates/grpcio-sys/grpcio-sys-0.6.0.crate"
+    value: "https://static.crates.io/crates/grpcio-sys/grpcio-sys-0.7.2.crate"
   }
-  version: "0.6.0"
+  version: "0.7.2"
   license_type: NOTICE
   last_upgrade_date {
     year: 2020
-    month: 10
-    day: 14
+    month: 12
+    day: 18
   }
 }
diff --git a/build.rs b/build.rs
index 3473239..44e1480 100644
--- a/build.rs
+++ b/build.rs
@@ -75,7 +75,9 @@
             println!("cargo:rustc-link-lib=framework=CoreFoundation");
         }
 
-        if env::var("CARGO_CFG_TARGET_ENV").unwrap() == "musl" {
+        if let Some(val) = get_env("CXX") {
+            config.define("CMAKE_CXX_COMPILER", val);
+        } else if env::var("CARGO_CFG_TARGET_ENV").unwrap() == "musl" {
             config.define("CMAKE_CXX_COMPILER", "g++");
         }