Merge pull request #23437 from lidizheng/update-support-message

Update the hint for install Python header to depend on version

src/python/grpcio/support.py

@@ -28,18 +28,25 @@ int main(int argc, char **argv) { return 0; }
 """
 C_PYTHON_DEV_ERROR_MESSAGE = """
 Could not find <Python.h>. This could mean the following:
-  * You're on Ubuntu and haven't run `apt-get install python-dev`.
-  * You're on RHEL/Fedora and haven't run `yum install python-devel` or
-    `dnf install python-devel` (make sure you also have redhat-rpm-config
+  * You're on Ubuntu and haven't run `apt-get install <PY_REPR>-dev`.
+  * You're on RHEL/Fedora and haven't run `yum install <PY_REPR>-devel` or
+    `dnf install <PY_REPR>-devel` (make sure you also have redhat-rpm-config
     installed)
   * You're on Mac OS X and the usual Python framework was somehow corrupted
     (check your environment variables or try re-installing?)
   * You're on Windows and your Python installation was somehow corrupted
     (check your environment variables or try re-installing?)
 """
+if sys.version_info[0] == 2:
+    PYTHON_REPRESENTATION = 'python'
+elif sys.version_info[0] == 3:
+    PYTHON_REPRESENTATION = 'python3'
+else:
+    raise NotImplementedError('Unsupported Python version: %s' % sys.version)
 
 C_CHECKS = {
-    C_PYTHON_DEV: C_PYTHON_DEV_ERROR_MESSAGE,
+    C_PYTHON_DEV:
+        C_PYTHON_DEV_ERROR_MESSAGE.replace('<PY_REPR>', PYTHON_REPRESENTATION),
 }