Output more debug information when running python tests

This is for debugging https://github.com/bazelbuild/bazel/issues/3273

Change-Id: I84e260ae1a22147fed0cffc2960352c77af2cf58
PiperOrigin-RevId: 160399209
diff --git a/tools/cpp/cc_configure.bzl b/tools/cpp/cc_configure.bzl
index 79fb8ba..c6eb2b8 100644
--- a/tools/cpp/cc_configure.bzl
+++ b/tools/cpp/cc_configure.bzl
@@ -51,6 +51,7 @@
         "BAZEL_VC",
         "BAZEL_VS",
         "CC",
+        "CC_CONFIGURE_DEBUG",
         "CC_TOOLCHAIN_NAME",
         "CPLUS_INCLUDE_PATH",
         "CUDA_COMPUTE_CAPABILITIES",