dev-python/grpcio-tools: respect CC in setup.py

Upstream-PR: https://github.com/grpc/grpc/pull/23159
Bug: https://bugs.gentoo.org/727478
Package-Manager: Portage-2.3.100, Repoman-2.3.22
Signed-off-by: Georgy Yakovlev <gyakovlev@gentoo.org>

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

@@ -0,0 +1,14 @@
+--- 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)

dev-python/grpcio-tools/grpcio-tools-1.28.1.ebuild

@@ -22,6 +22,8 @@ DEPEND="${RDEPEND}
 	dev-python/setuptools[${PYTHON_USEDEP}]
 "
 
+PATCHES=( "${FILESDIR}/setup.py-respect-cc.patch" )
+
 python_configure_all() {
 	export GRPC_PYTHON_BUILD_WITH_CYTHON=1
 	export GRPC_PYTHON_BUILD_EXT_COMPILER_JOBS="$(makeopts_jobs)"