gentoo-overlay/dev-python/grpcio-tools/files/setup.py-respect-cc.patch

--- a/setup.py	2020-06-08 00:11:23.457959701 -0700
+++ b/setup.py	2020-06-08 00:11:54.384652323 -0700
@@ -68,9 +68,10 @@
 
 def check_linker_need_libatomic():
     """Test if linker on system needs libatomic."""
+    cc = os.environ.get('CC', 'cc')
     code_test = (b'#include <atomic>\n' +
                  b'int main() { return std::atomic<int64_t>{}; }')
-    cc_test = subprocess.Popen(['cc', '-x', 'c++', '-std=c++11', '-'],
+    cc_test = subprocess.Popen([cc, '-x', 'c++', '-std=c++11', '-'],
                                stdin=PIPE,
                                stdout=PIPE,
                                stderr=PIPE)