diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c
index eb1f1a01feeca8..3304195bd75e99 100644
--- a/Modules/_decimal/_decimal.c
+++ b/Modules/_decimal/_decimal.c
@@ -3284,7 +3284,7 @@ dec_format(PyObject *dec, PyObject *args)
     }
     else {
         size_t n = strlen(spec.dot);
-        if (n > 1 || (n == 1 && !isascii((uchar)spec.dot[0]))) {
+        if (n > 1 || (n == 1 && !isascii((unsigned char)spec.dot[0]))) {
             /* fix locale dependent non-ascii characters */
             dot = dotsep_as_utf8(spec.dot);
             if (dot == NULL) {
@@ -3293,7 +3293,7 @@ dec_format(PyObject *dec, PyObject *args)
             spec.dot = PyBytes_AS_STRING(dot);
         }
         n = strlen(spec.sep);
-        if (n > 1 || (n == 1 && !isascii((uchar)spec.sep[0]))) {
+        if (n > 1 || (n == 1 && !isascii((unsigned char)spec.sep[0]))) {
             /* fix locale dependent non-ascii characters */
             sep = dotsep_as_utf8(spec.sep);
             if (sep == NULL) {
diff --git a/setup.py b/setup.py
index d5b1fddab95442..24ca06a232971a 100644
--- a/setup.py
+++ b/setup.py
@@ -2065,7 +2065,7 @@ def detect_decimal(self):
         undef_macros = []
         if '--with-system-libmpdec' in sysconfig.get_config_var("CONFIG_ARGS"):
             include_dirs = []
-            libraries = [':libmpdec.so.2']
+            libraries = ['mpdec']
             sources = ['_decimal/_decimal.c']
             depends = ['_decimal/docstrings.h']
         else: