--- gmpy-gmpy2-2.1.0b4/src/gmpy2.c.orig	2020-02-04 05:36:50.000000000 +0100
+++ gmpy-gmpy2-2.1.0b4/src/gmpy2.c	2020-04-07 21:48:24.187539100 +0200
@@ -932,7 +932,7 @@
 
     /* Validate the sizes of the various typedef'ed integer types. */
 
-#if defined _WIN64 && (MPIR || MSYS2)
+#if defined _WIN64 && MPIR
     if (sizeof(mp_bitcnt_t) != sizeof(PY_LONG_LONG)) {
         /* LCOV_EXCL_START */
         SYSTEM_ERROR("Size of PY_LONG_LONG and mp_bitcnt_t not compatible (_WIN64 && MPIR)");
--- gmpy-gmpy2-2.1.0b4/src/gmpy2_convert_utils.h.orig	2020-02-04 05:36:50.000000000 +0100
+++ gmpy-gmpy2-2.1.0b4/src/gmpy2_convert_utils.h	2020-04-07 21:48:30.754303500 +0200
@@ -53,7 +53,7 @@
  * builds has been changed to unsigned long long int.
  */
 
-#if defined _WIN64 && (MPIR || MSYS2)
+#if defined _WIN64 && MPIR
 # define mp_bitcnt_t_From_Integer c_ulonglong_From_Integer
 # define GMPy_Integer_AsMpBitCntAndError GMPy_Integer_AsUnsignedLongLongAndError
 #else
