diff --git a/include/grpc/impl/codegen/compression_types.h b/include/grpc/impl/codegen/compression_types.h
index f552d3c8a28afe8360e5826fe377dd32ca049a33..94a10da21b6bf7fd7ef82dbb9ab6ea2b84e3eee4 100644
--- a/include/grpc/impl/codegen/compression_types.h
+++ b/include/grpc/impl/codegen/compression_types.h
@@ -34,7 +34,7 @@
 #ifndef GRPC_IMPL_CODEGEN_COMPRESSION_TYPES_H
 #define GRPC_IMPL_CODEGEN_COMPRESSION_TYPES_H
 
-#include <stdint.h>
+#include <grpc/support/port_platform.h>
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/include/grpc/impl/codegen/port_platform.h b/include/grpc/impl/codegen/port_platform.h
index d5294b2efa8b5f8e68873a4fb98e7b21fa1d8f39..61cee9a5b1090e48ab82cc076142c498baba8624 100644
--- a/include/grpc/impl/codegen/port_platform.h
+++ b/include/grpc/impl/codegen/port_platform.h
@@ -34,6 +34,23 @@
 #ifndef GRPC_IMPL_CODEGEN_PORT_PLATFORM_H
 #define GRPC_IMPL_CODEGEN_PORT_PLATFORM_H
 
+#ifdef _MSC_VER
+#if _MSC_VER < 1700
+typedef __int8 int8_t;
+typedef __int16 int16_t;
+typedef __int32 int32_t;
+typedef __int64 int64_t;
+typedef unsigned __int8 uint8_t;
+typedef unsigned __int16 uint16_t;
+typedef unsigned __int32 uint32_t;
+typedef unsigned __int64 uint64_t;
+#else
+#include <stdint.h>
+#endif /* _MSC_VER < 1700 */
+#else
+#include <stdint.h>
+#endif /* _MSC_VER */
+
 /* Get windows.h included everywhere (we need it) */
 #if defined(_WIN64) || defined(WIN64) || defined(_WIN32) || defined(WIN32)
 #ifndef WIN32_LEAN_AND_MEAN
@@ -254,10 +271,6 @@
 #define GPR_FORBID_UNREACHABLE_CODE 1
 #endif
 
-/* For a common case, assume that the platform has a C99-like stdint.h */
-
-#include <stdint.h>
-
 /* Cache line alignment */
 #ifndef GPR_CACHELINE_SIZE_LOG
 #if defined(__i386__) || defined(__x86_64__)
diff --git a/include/grpc/impl/codegen/propagation_bits.h b/include/grpc/impl/codegen/propagation_bits.h
index 989b86f2aad8f06531bbc61af37a8eb78582bbc3..d03641559974ba89335787a3edc5daa25bab754e 100644
--- a/include/grpc/impl/codegen/propagation_bits.h
+++ b/include/grpc/impl/codegen/propagation_bits.h
@@ -34,7 +34,7 @@
 #ifndef GRPC_IMPL_CODEGEN_H
 #define GRPC_IMPL_CODEGEN_H
 
-#include <stdint.h>
+#include <grpc/support/port_platform.h>
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/setup.py b/setup.py
index 1a3c838a10e36d0e4d6ba51c8d46360d1b3ebb16..d73286f88fe23660c00b575e15db105a5ee56ba4 100644
--- a/setup.py
+++ b/setup.py
@@ -82,14 +82,16 @@ CYTHON_HELPER_C_FILES = (
 
 CORE_C_FILES = ()
 if not "win32" in sys.platform:
-    CORE_C_FILES += tuple(grpc_core_dependencies.CORE_SOURCE_FILES)
+  CORE_C_FILES += tuple(grpc_core_dependencies.CORE_SOURCE_FILES)
 
 EXTENSION_INCLUDE_DIRECTORIES = (
     (PYTHON_STEM,) + CORE_INCLUDE + BORINGSSL_INCLUDE + ZLIB_INCLUDE)
 
-EXTENSION_LIBRARIES = ('m',)
+EXTENSION_LIBRARIES = ()
 if "linux" in sys.platform:
-    EXTENSION_LIBRARIES += ('rt',)
+  EXTENSION_LIBRARIES += ('rt',)
+if not "win32" in sys.platform:
+  EXTENSION_LIBRARIES += ('m',)
 
 DEFINE_MACROS = (('OPENSSL_NO_ASM', 1), ('_WIN32_WINNT', 0x600))
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi
index 1295009809dcb4f43c3138a5c75f562166c3fcbc..9d6e0170269fe12febbbc75f3864897fd4eee64e 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi
@@ -28,11 +28,14 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 cimport libc.time
-from libc.stdint cimport int64_t, uint32_t, int32_t
 
 
 cdef extern from "grpc/_cython/loader.h":
 
+  ctypedef int int32_t
+  ctypedef unsigned uint32_t
+  ctypedef long int64_t
+
   int pygrpc_load_core(const char*)
 
   void *gpr_malloc(size_t size)
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi
index d7ad9e5215bdfb98697df0cbf6af89e9f0bef95f..9e14b967e0aa3dcd1e4fc422ab1b2989f59b7061 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi
@@ -146,8 +146,13 @@ cdef class Timespec:
         gpr_convert_clock_type(self.c_time, GPR_CLOCK_REALTIME))
     return <double>real_time.seconds + <double>real_time.nanoseconds / 1e9
 
-  infinite_future = Timespec(float("+inf"))
-  infinite_past = Timespec(float("-inf"))
+  @staticmethod
+  def infinite_future():
+    return Timespec(float("+inf"))
+
+  @staticmethod
+  def infinite_past():
+    return Timespec(float("-inf"))
 
 
 cdef class CallDetails:
diff --git a/src/python/grpcio/grpc/_cython/cygrpc.pyx b/src/python/grpcio/grpc/_cython/cygrpc.pyx
index fd1443e79046fc3a8469db34c1d9b6f12a7ecf03..3967c3045f72da3d627a73b984488c9c1b49f741 100644
--- a/src/python/grpcio/grpc/_cython/cygrpc.pyx
+++ b/src/python/grpcio/grpc/_cython/cygrpc.pyx
@@ -47,16 +47,19 @@ include "grpc/_cython/_cygrpc/server.pyx.pxi"
 
 cdef class _ModuleState:
 
+  cdef bint is_loaded
+
   def __cinit__(self):
     filename = pkg_resources.resource_filename(
-        __name__, '_windows/grpc_c.64.python')
-    directory = os.path.dirname(filename)
-    if not pygrpc_load_core(directory):
+        'grpc._cython', '_windows/grpc_c.64.python')
+    if not pygrpc_load_core(filename):
       raise ImportError('failed to load core gRPC library')
     grpc_init()
+    self.is_loaded = True
 
   def __dealloc__(self):
-    grpc_shutdown()
+    if self.is_loaded:
+      grpc_shutdown()
 
 _module_state = _ModuleState()