diff --git a/Lib/decimal.py b/Lib/decimal.py
index 96d9df4a8c8..9f37e4fa48e 100644
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -140,6 +140,7 @@ __all__ = [
 
 __version__ = '1.70'    # Highest version of the spec this complies with
                         # See http://speleotrove.com/decimal/
+__libmpdec_version__ = "2.4.0" # compatible libmpdec version
 
 import copy as _copy
 import math as _math
diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py
index 71b93a661b6..54a3615e9cd 100644
--- a/Lib/test/test_decimal.py
+++ b/Lib/test/test_decimal.py
@@ -4150,6 +4150,7 @@ class CheckAttributes(unittest.TestCase):
         self.assertTrue(P.HAVE_THREADS is True or P.HAVE_THREADS is False)
 
         self.assertEqual(C.__version__, P.__version__)
+        self.assertEqual(C.__libmpdec_version__, P.__libmpdec_version__)
 
         x = dir(C)
         y = [s for s in dir(P) if '__' in s or not s.startswith('_')]
diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c
index 06c2c395b87..ac20308953a 100644
--- a/Modules/_decimal/_decimal.c
+++ b/Modules/_decimal/_decimal.c
@@ -39,6 +39,11 @@
 #include "memory.h"
 
 
+#if MPD_MAJOR_VERSION != 2
+  #error "libmpdec major version 2 required"
+#endif
+
+
 /*
  * Type sizes with assertions in mpdecimal.h and pyport.h:
  *    sizeof(size_t) == sizeof(Py_ssize_t)
@@ -5730,7 +5735,8 @@ PyInit__decimal(void)
     }
 
     /* Add specification version number */
-    CHECK_INT(PyModule_AddStringConstant(m, "__version__", " 1.70"));
+    CHECK_INT(PyModule_AddStringConstant(m, "__version__", "1.70"));
+    CHECK_INT(PyModule_AddStringConstant(m, "__libmpdec_version__", mpd_version()));
 
 
     return m;
diff --git a/Modules/_decimal/libmpdec/mpdecimal.c b/Modules/_decimal/libmpdec/mpdecimal.c
index c63a1a08e49..287a77ed302 100644
--- a/Modules/_decimal/libmpdec/mpdecimal.c
+++ b/Modules/_decimal/libmpdec/mpdecimal.c
@@ -97,6 +97,8 @@ static void _settriple(mpd_t *result, uint8_t sign, mpd_uint_t a,
                        mpd_ssize_t exp);
 static inline mpd_ssize_t _mpd_real_size(mpd_uint_t *data, mpd_ssize_t size);
 
+static int _mpd_cmp_abs(const mpd_t *a, const mpd_t *b);
+
 static void _mpd_qadd(mpd_t *result, const mpd_t *a, const mpd_t *b,
                       const mpd_context_t *ctx, uint32_t *status);
 static inline void _mpd_qmul(mpd_t *result, const mpd_t *a, const mpd_t *b,
@@ -110,6 +112,17 @@ static inline void _mpd_qpow_uint(mpd_t *result, const mpd_t *base,
 static mpd_uint_t mpd_qsshiftr(mpd_t *result, const mpd_t *a, mpd_ssize_t n);
 
 
+/******************************************************************************/
+/*                                  Version                                   */
+/******************************************************************************/
+
+const char *
+mpd_version(void)
+{
+    return MPD_VERSION;
+}
+
+
 /******************************************************************************/
 /*                  Performance critical inline functions                     */
 /******************************************************************************/
@@ -1345,6 +1358,91 @@ mpd_qget_ssize(const mpd_t *a, uint32_t *status)
     return MPD_SSIZE_MAX;
 }
 
+#if defined(CONFIG_32) && !defined(LEGACY_COMPILER)
+/*
+ * Quietly get a uint64_t from a decimal. If the operation is impossible,
+ * MPD_Invalid_operation is set.
+ */
+static uint64_t
+_c32_qget_u64(int use_sign, const mpd_t *a, uint32_t *status)
+{
+    MPD_NEW_STATIC(tmp,0,0,20,3);
+    mpd_context_t maxcontext;
+    uint64_t ret;
+
+    tmp_data[0] = 709551615;
+    tmp_data[1] = 446744073;
+    tmp_data[2] = 18;
+
+    if (mpd_isspecial(a)) {
+        *status |= MPD_Invalid_operation;
+        return UINT64_MAX;
+    }
+    if (mpd_iszero(a)) {
+        return 0;
+    }
+    if (use_sign && mpd_isnegative(a)) {
+        *status |= MPD_Invalid_operation;
+        return UINT64_MAX;
+    }
+    if (!_mpd_isint(a)) {
+        *status |= MPD_Invalid_operation;
+        return UINT64_MAX;
+    }
+
+    if (_mpd_cmp_abs(a, &tmp) > 0) {
+        *status |= MPD_Invalid_operation;
+        return UINT64_MAX;
+    }
+
+    mpd_maxcontext(&maxcontext);
+    mpd_qrescale(&tmp, a, 0, &maxcontext, &maxcontext.status);
+    maxcontext.status &= ~MPD_Rounded;
+    if (maxcontext.status != 0) {
+        *status |= (maxcontext.status|MPD_Invalid_operation); /* GCOV_NOT_REACHED */
+        return UINT64_MAX; /* GCOV_NOT_REACHED */
+    }
+
+    ret = 0;
+    switch (tmp.len) {
+    case 3:
+        ret += (uint64_t)tmp_data[2] * 1000000000000000000ULL;
+    case 2:
+        ret += (uint64_t)tmp_data[1] * 1000000000ULL;
+    case 1:
+        ret += tmp_data[0];
+        break;
+    default:
+        abort(); /* GCOV_NOT_REACHED */
+    }
+
+    return ret;
+}
+
+static int64_t
+_c32_qget_i64(const mpd_t *a, uint32_t *status)
+{
+    uint64_t u;
+    int isneg;
+
+    u = _c32_qget_u64(0, a, status);
+    if (*status&MPD_Invalid_operation) {
+        return INT64_MAX;
+    }
+
+    isneg = mpd_isnegative(a);
+    if (u <= INT64_MAX) {
+        return isneg ? -((int64_t)u) : (int64_t)u;
+    }
+    else if (isneg && u+(INT64_MIN+INT64_MAX) == INT64_MAX) {
+        return INT64_MIN;
+    }
+
+    *status |= MPD_Invalid_operation;
+    return INT64_MAX;
+}
+#endif /* CONFIG_32 && !LEGACY_COMPILER */
+
 #ifdef CONFIG_64
 /* quietly get a uint64_t from a decimal */
 uint64_t
@@ -1359,7 +1457,57 @@ mpd_qget_i64(const mpd_t *a, uint32_t *status)
 {
     return mpd_qget_ssize(a, status);
 }
+
+/* quietly get a uint32_t from a decimal */
+uint32_t
+mpd_qget_u32(const mpd_t *a, uint32_t *status)
+{
+    uint64_t x = mpd_qget_uint(a, status);
+
+    if (*status&MPD_Invalid_operation) {
+        return UINT32_MAX;
+    }
+    if (x > UINT32_MAX) {
+        *status |= MPD_Invalid_operation;
+        return UINT32_MAX;
+    }
+
+    return (uint32_t)x;
+}
+
+/* quietly get an int32_t from a decimal */
+int32_t
+mpd_qget_i32(const mpd_t *a, uint32_t *status)
+{
+    int64_t x = mpd_qget_ssize(a, status);
+
+    if (*status&MPD_Invalid_operation) {
+        return INT32_MAX;
+    }
+    if (x < INT32_MIN || x > INT32_MAX) {
+        *status |= MPD_Invalid_operation;
+        return INT32_MAX;
+    }
+
+    return (int32_t)x;
+}
 #else
+#ifndef LEGACY_COMPILER
+/* quietly get a uint64_t from a decimal */
+uint64_t
+mpd_qget_u64(const mpd_t *a, uint32_t *status)
+{
+    return _c32_qget_u64(1, a, status);
+}
+
+/* quietly get an int64_t from a decimal */
+int64_t
+mpd_qget_i64(const mpd_t *a, uint32_t *status)
+{
+    return _c32_qget_i64(a, status);
+}
+#endif
+
 /* quietly get a uint32_t from a decimal */
 uint32_t
 mpd_qget_u32(const mpd_t *a, uint32_t *status)
@@ -3386,6 +3534,34 @@ mpd_qadd_u64(mpd_t *result, const mpd_t *a, uint64_t b,
 {
     mpd_qadd_uint(result, a, b, ctx, status);
 }
+#elif !defined(LEGACY_COMPILER)
+/* Add decimal and int64_t. */
+void
+mpd_qadd_i64(mpd_t *result, const mpd_t *a, int64_t b,
+             const mpd_context_t *ctx, uint32_t *status)
+{
+    mpd_context_t maxcontext;
+    MPD_NEW_STATIC(bb,0,0,0,0);
+
+    mpd_maxcontext(&maxcontext);
+    mpd_qset_i64(&bb, b, &maxcontext, status);
+    mpd_qadd(result, a, &bb, ctx, status);
+    mpd_del(&bb);
+}
+
+/* Add decimal and uint64_t. */
+void
+mpd_qadd_u64(mpd_t *result, const mpd_t *a, uint64_t b,
+             const mpd_context_t *ctx, uint32_t *status)
+{
+    mpd_context_t maxcontext;
+    MPD_NEW_STATIC(bb,0,0,0,0);
+
+    mpd_maxcontext(&maxcontext);
+    mpd_qset_u64(&bb, b, &maxcontext, status);
+    mpd_qadd(result, a, &bb, ctx, status);
+    mpd_del(&bb);
+}
 #endif
 
 /* Subtract int32_t from decimal. */
@@ -3420,6 +3596,34 @@ mpd_qsub_u64(mpd_t *result, const mpd_t *a, uint64_t b,
 {
     mpd_qsub_uint(result, a, b, ctx, status);
 }
+#elif !defined(LEGACY_COMPILER)
+/* Subtract int64_t from decimal. */
+void
+mpd_qsub_i64(mpd_t *result, const mpd_t *a, int64_t b,
+             const mpd_context_t *ctx, uint32_t *status)
+{
+    mpd_context_t maxcontext;
+    MPD_NEW_STATIC(bb,0,0,0,0);
+
+    mpd_maxcontext(&maxcontext);
+    mpd_qset_i64(&bb, b, &maxcontext, status);
+    mpd_qsub(result, a, &bb, ctx, status);
+    mpd_del(&bb);
+}
+
+/* Subtract uint64_t from decimal. */
+void
+mpd_qsub_u64(mpd_t *result, const mpd_t *a, uint64_t b,
+             const mpd_context_t *ctx, uint32_t *status)
+{
+    mpd_context_t maxcontext;
+    MPD_NEW_STATIC(bb,0,0,0,0);
+
+    mpd_maxcontext(&maxcontext);
+    mpd_qset_u64(&bb, b, &maxcontext, status);
+    mpd_qsub(result, a, &bb, ctx, status);
+    mpd_del(&bb);
+}
 #endif
 
 
@@ -3871,6 +4075,34 @@ mpd_qdiv_u64(mpd_t *result, const mpd_t *a, uint64_t b,
 {
     mpd_qdiv_uint(result, a, b, ctx, status);
 }
+#elif !defined(LEGACY_COMPILER)
+/* Divide decimal by int64_t. */
+void
+mpd_qdiv_i64(mpd_t *result, const mpd_t *a, int64_t b,
+             const mpd_context_t *ctx, uint32_t *status)
+{
+    mpd_context_t maxcontext;
+    MPD_NEW_STATIC(bb,0,0,0,0);
+
+    mpd_maxcontext(&maxcontext);
+    mpd_qset_i64(&bb, b, &maxcontext, status);
+    mpd_qdiv(result, a, &bb, ctx, status);
+    mpd_del(&bb);
+}
+
+/* Divide decimal by uint64_t. */
+void
+mpd_qdiv_u64(mpd_t *result, const mpd_t *a, uint64_t b,
+             const mpd_context_t *ctx, uint32_t *status)
+{
+    mpd_context_t maxcontext;
+    MPD_NEW_STATIC(bb,0,0,0,0);
+
+    mpd_maxcontext(&maxcontext);
+    mpd_qset_u64(&bb, b, &maxcontext, status);
+    mpd_qdiv(result, a, &bb, ctx, status);
+    mpd_del(&bb);
+}
 #endif
 
 /* Pad the result with trailing zeros if it has fewer digits than prec. */
@@ -5664,6 +5896,34 @@ mpd_qmul_u64(mpd_t *result, const mpd_t *a, uint64_t b,
 {
     mpd_qmul_uint(result, a, b, ctx, status);
 }
+#elif !defined(LEGACY_COMPILER)
+/* Multiply decimal and int64_t. */
+void
+mpd_qmul_i64(mpd_t *result, const mpd_t *a, int64_t b,
+             const mpd_context_t *ctx, uint32_t *status)
+{
+    mpd_context_t maxcontext;
+    MPD_NEW_STATIC(bb,0,0,0,0);
+
+    mpd_maxcontext(&maxcontext);
+    mpd_qset_i64(&bb, b, &maxcontext, status);
+    mpd_qmul(result, a, &bb, ctx, status);
+    mpd_del(&bb);
+}
+
+/* Multiply decimal and uint64_t. */
+void
+mpd_qmul_u64(mpd_t *result, const mpd_t *a, uint64_t b,
+             const mpd_context_t *ctx, uint32_t *status)
+{
+    mpd_context_t maxcontext;
+    MPD_NEW_STATIC(bb,0,0,0,0);
+
+    mpd_maxcontext(&maxcontext);
+    mpd_qset_u64(&bb, b, &maxcontext, status);
+    mpd_qmul(result, a, &bb, ctx, status);
+    mpd_del(&bb);
+}
 #endif
 
 /* Like the minus operator. */
diff --git a/Modules/_decimal/libmpdec/mpdecimal.h b/Modules/_decimal/libmpdec/mpdecimal.h
index 06f54708dc5..0f31733cb75 100644
--- a/Modules/_decimal/libmpdec/mpdecimal.h
+++ b/Modules/_decimal/libmpdec/mpdecimal.h
@@ -32,7 +32,6 @@
 
 #ifdef __cplusplus
 extern "C" {
-#define __STDC_LIMIT_MACROS
 #endif
 
 
@@ -56,12 +55,18 @@ extern "C" {
   #define MPD_HIDE_SYMBOLS_END
   #define EXTINLINE extern inline
 #else
-  #ifdef HAVE_STDINT_H
-    #include <stdint.h>
-  #endif
   #ifdef HAVE_INTTYPES_H
     #include <inttypes.h>
   #endif
+  #ifdef HAVE_STDINT_H
+    #if defined(__cplusplus) && !defined(__STDC_LIMIT_MACROS)
+      #define __STDC_LIMIT_MACROS
+      #include <stdint.h>
+      #undef __STDC_LIMIT_MACROS
+    #else
+      #include <stdint.h>
+    #endif
+  #endif
   #ifndef __GNUC_STDC_INLINE__
     #define __GNUC_STDC_INLINE__ 1
   #endif
@@ -99,6 +104,19 @@ MPD_PRAGMA(MPD_HIDE_SYMBOLS_START)
 #endif
 
 
+/******************************************************************************/
+/*                                  Version                                   */
+/******************************************************************************/
+
+#define MPD_MAJOR_VERSION 2
+#define MPD_MINOR_VERSION 4
+#define MPD_MICRO_VERSION 0
+
+#define MPD_VERSION "2.4.0"
+
+const char *mpd_version(void);
+
+
 /******************************************************************************/
 /*                              Configuration                                 */
 /******************************************************************************/
@@ -241,7 +259,7 @@ extern const char *mpd_round_string[MPD_ROUND_GUARD];
 extern const char *mpd_clamp_string[MPD_CLAMP_GUARD];
 
 
-typedef struct {
+typedef struct mpd_context_t {
     mpd_ssize_t prec;   /* precision */
     mpd_ssize_t emax;   /* max positive exp */
     mpd_ssize_t emin;   /* min negative exp */
@@ -353,7 +371,7 @@ void mpd_addstatus_raise(mpd_context_t *ctx, uint32_t flags);
 #define MPD_DATAFLAGS (MPD_STATIC_DATA|MPD_SHARED_DATA|MPD_CONST_DATA)
 
 /* mpd_t */
-typedef struct {
+typedef struct mpd_t {
     uint8_t flags;
     mpd_ssize_t exp;
     mpd_ssize_t digits;
@@ -371,7 +389,7 @@ typedef unsigned char uchar;
 /******************************************************************************/
 
 /* format specification */
-typedef struct {
+typedef struct mpd_spec_t {
     mpd_ssize_t min_width; /* minimum field width */
     mpd_ssize_t prec;      /* fraction digits or significant digits */
     char type;             /* conversion specifier */
@@ -437,6 +455,12 @@ mpd_ssize_t mpd_qget_ssize(const mpd_t *dec, uint32_t *status);
 mpd_uint_t mpd_qget_uint(const mpd_t *dec, uint32_t *status);
 mpd_uint_t mpd_qabs_uint(const mpd_t *dec, uint32_t *status);
 
+int32_t mpd_qget_i32(const mpd_t *dec, uint32_t *status);
+uint32_t mpd_qget_u32(const mpd_t *dec, uint32_t *status);
+#ifndef LEGACY_COMPILER
+int64_t mpd_qget_i64(const mpd_t *dec, uint32_t *status);
+uint64_t mpd_qget_u64(const mpd_t *dec, uint32_t *status);
+#endif
 
 /* quiet functions */
 int mpd_qcheck_nan(mpd_t *nanresult, const mpd_t *a, const mpd_context_t *ctx, uint32_t *status);
@@ -528,6 +552,17 @@ void mpd_qlog10(mpd_t *result, const mpd_t *a, const mpd_context_t *ctx, uint32_
 void mpd_qsqrt(mpd_t *result, const mpd_t *a, const mpd_context_t *ctx, uint32_t *status);
 void mpd_qinvroot(mpd_t *result, const mpd_t *a, const mpd_context_t *ctx, uint32_t *status);
 
+#ifndef LEGACY_COMPILER
+void mpd_qadd_i64(mpd_t *result, const mpd_t *a, int64_t b, const mpd_context_t *ctx, uint32_t *status);
+void mpd_qadd_u64(mpd_t *result, const mpd_t *a, uint64_t b, const mpd_context_t *ctx, uint32_t *status);
+void mpd_qsub_i64(mpd_t *result, const mpd_t *a, int64_t b, const mpd_context_t *ctx, uint32_t *status);
+void mpd_qsub_u64(mpd_t *result, const mpd_t *a, uint64_t b, const mpd_context_t *ctx, uint32_t *status);
+void mpd_qmul_i64(mpd_t *result, const mpd_t *a, int64_t b, const mpd_context_t *ctx, uint32_t *status);
+void mpd_qmul_u64(mpd_t *result, const mpd_t *a, uint64_t b, const mpd_context_t *ctx, uint32_t *status);
+void mpd_qdiv_i64(mpd_t *result, const mpd_t *a, int64_t b, const mpd_context_t *ctx, uint32_t *status);
+void mpd_qdiv_u64(mpd_t *result, const mpd_t *a, uint64_t b, const mpd_context_t *ctx, uint32_t *status);
+#endif
+
 
 size_t mpd_sizeinbase(const mpd_t *a, uint32_t base);
 void mpd_qimport_u16(mpd_t *result, const uint16_t *srcdata, size_t srclen,
@@ -571,6 +606,12 @@ void mpd_set_u64(mpd_t *result, uint64_t a, mpd_context_t *ctx);
 mpd_ssize_t mpd_get_ssize(const mpd_t *a, mpd_context_t *ctx);
 mpd_uint_t mpd_get_uint(const mpd_t *a, mpd_context_t *ctx);
 mpd_uint_t mpd_abs_uint(const mpd_t *a, mpd_context_t *ctx);
+int32_t mpd_get_i32(const mpd_t *a, mpd_context_t *ctx);
+uint32_t mpd_get_u32(const mpd_t *a, mpd_context_t *ctx);
+#ifndef LEGACY_COMPILER
+int64_t mpd_get_i64(const mpd_t *a, mpd_context_t *ctx);
+uint64_t mpd_get_u64(const mpd_t *a, mpd_context_t *ctx);
+#endif
 void mpd_and(mpd_t *result, const mpd_t *a, const mpd_t *b, mpd_context_t *ctx);
 void mpd_copy(mpd_t *result, const mpd_t *a, mpd_context_t *ctx);
 void mpd_canonical(mpd_t *result, const mpd_t *a, mpd_context_t *ctx);
@@ -641,31 +682,7 @@ void mpd_ceil(mpd_t *result, const mpd_t *a, mpd_context_t *ctx);
 void mpd_sqrt(mpd_t *result, const mpd_t *a, mpd_context_t *ctx);
 void mpd_invroot(mpd_t *result, const mpd_t *a, mpd_context_t *ctx);
 
-
-/******************************************************************************/
-/*                          Configuration specific                            */
-/******************************************************************************/
-
-#ifdef CONFIG_64
-void mpd_qsset_i64(mpd_t *result, int64_t a, const mpd_context_t *ctx, uint32_t *status);
-void mpd_qsset_u64(mpd_t *result, uint64_t a, const mpd_context_t *ctx, uint32_t *status);
-int64_t mpd_qget_i64(const mpd_t *dec, uint32_t *status);
-uint64_t mpd_qget_u64(const mpd_t *dec, uint32_t *status);
-
-void mpd_qadd_i64(mpd_t *result, const mpd_t *a, int64_t b, const mpd_context_t *ctx, uint32_t *status);
-void mpd_qadd_u64(mpd_t *result, const mpd_t *a, uint64_t b, const mpd_context_t *ctx, uint32_t *status);
-void mpd_qsub_i64(mpd_t *result, const mpd_t *a, int64_t b, const mpd_context_t *ctx, uint32_t *status);
-void mpd_qsub_u64(mpd_t *result, const mpd_t *a, uint64_t b, const mpd_context_t *ctx, uint32_t *status);
-void mpd_qmul_i64(mpd_t *result, const mpd_t *a, int64_t b, const mpd_context_t *ctx, uint32_t *status);
-void mpd_qmul_u64(mpd_t *result, const mpd_t *a, uint64_t b, const mpd_context_t *ctx, uint32_t *status);
-void mpd_qdiv_i64(mpd_t *result, const mpd_t *a, int64_t b, const mpd_context_t *ctx, uint32_t *status);
-void mpd_qdiv_u64(mpd_t *result, const mpd_t *a, uint64_t b, const mpd_context_t *ctx, uint32_t *status);
-
-void mpd_sset_i64(mpd_t *result, int64_t a, mpd_context_t *ctx);
-void mpd_sset_u64(mpd_t *result, uint64_t a, mpd_context_t *ctx);
-int64_t mpd_get_i64(const mpd_t *a, mpd_context_t *ctx);
-uint64_t mpd_get_u64(const mpd_t *a, mpd_context_t *ctx);
-
+#ifndef LEGACY_COMPILER
 void mpd_add_i64(mpd_t *result, const mpd_t *a, int64_t b, mpd_context_t *ctx);
 void mpd_add_u64(mpd_t *result, const mpd_t *a, uint64_t b, mpd_context_t *ctx);
 void mpd_sub_i64(mpd_t *result, const mpd_t *a, int64_t b, mpd_context_t *ctx);
@@ -674,11 +691,18 @@ void mpd_div_i64(mpd_t *result, const mpd_t *a, int64_t b, mpd_context_t *ctx);
 void mpd_div_u64(mpd_t *result, const mpd_t *a, uint64_t b, mpd_context_t *ctx);
 void mpd_mul_i64(mpd_t *result, const mpd_t *a, int64_t b, mpd_context_t *ctx);
 void mpd_mul_u64(mpd_t *result, const mpd_t *a, uint64_t b, mpd_context_t *ctx);
-#else
-int32_t mpd_qget_i32(const mpd_t *dec, uint32_t *status);
-uint32_t mpd_qget_u32(const mpd_t *dec, uint32_t *status);
-int32_t mpd_get_i32(const mpd_t *a, mpd_context_t *ctx);
-uint32_t mpd_get_u32(const mpd_t *a, mpd_context_t *ctx);
+#endif
+
+
+/******************************************************************************/
+/*                          Configuration specific                            */
+/******************************************************************************/
+
+#ifdef CONFIG_64
+void mpd_qsset_i64(mpd_t *result, int64_t a, const mpd_context_t *ctx, uint32_t *status);
+void mpd_qsset_u64(mpd_t *result, uint64_t a, const mpd_context_t *ctx, uint32_t *status);
+void mpd_sset_i64(mpd_t *result, int64_t a, mpd_context_t *ctx);
+void mpd_sset_u64(mpd_t *result, uint64_t a, mpd_context_t *ctx);
 #endif
 
 
diff --git a/setup.py b/setup.py
index 19a7b291e13..906401404df 100644
--- a/setup.py
+++ b/setup.py
@@ -1945,7 +1945,7 @@ class PyBuildExt(build_ext):
         undef_macros = []
         if '--with-system-libmpdec' in sysconfig.get_config_var("CONFIG_ARGS"):
             include_dirs = []
-            libraries = ['mpdec']
+            libraries = [':libmpdec.so.2']
             sources = ['_decimal/_decimal.c']
             depends = ['_decimal/docstrings.h']
         else: