Issue #7652: Enable linking of _decimal.so against an installed libmpdec.

Misc/NEWS

@@ -34,6 +34,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #7652: Add --with-system-libmpdec option to configure for linking
+  the _decimal module against an installed libmpdec.
+
 - Issue #14380: MIMEText now defaults to utf-8 when passed non-ASCII unicode
   with no charset specified.
 

configure

@@ -762,6 +762,7 @@ with_pydebug
 with_libs
 with_system_expat
 with_system_ffi
+with_system_libmpdec
 enable_loadable_sqlite_extensions
 with_dbmliborder
 with_signal_module
@@ -1434,6 +1435,8 @@ Optional Packages:
   --with-system-expat     build pyexpat module using an installed expat
                           library
   --with-system-ffi       build _ctypes module using an installed ffi library
+  --with-system-libmpdec  build _decimal module using an installed libmpdec
+                          library
   --with-dbmliborder=db1:db2:...
                           order to check db backends for dbm. Valid value is a
                           colon separated string with the backend names
@@ -8501,6 +8504,21 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_system_ffi" >&5
 $as_echo "$with_system_ffi" >&6; }
 
+# Check for use of the system libmpdec library
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-system-libmpdec" >&5
+$as_echo_n "checking for --with-system-libmpdec... " >&6; }
+
+# Check whether --with-system_libmpdec was given.
+if test "${with_system_libmpdec+set}" = set; then :
+  withval=$with_system_libmpdec;
+else
+  with_system_libmpdec="no"
+fi
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_system_libmpdec" >&5
+$as_echo "$with_system_libmpdec" >&6; }
+
 # Check for support for loadable sqlite extensions
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for --enable-loadable-sqlite-extensions" >&5
 $as_echo_n "checking for --enable-loadable-sqlite-extensions... " >&6; }

configure.ac

@@ -2048,6 +2048,15 @@ AC_SUBST(LIBFFI_INCLUDEDIR)
 
 AC_MSG_RESULT($with_system_ffi)
 
+# Check for use of the system libmpdec library
+AC_MSG_CHECKING(for --with-system-libmpdec)
+AC_ARG_WITH(system_libmpdec,
+            AS_HELP_STRING([--with-system-libmpdec], [build _decimal module using an installed libmpdec library]),
+            [],
+            [with_system_libmpdec="no"])
+
+AC_MSG_RESULT($with_system_libmpdec)
+
 # Check for support for loadable sqlite extensions
 AC_MSG_CHECKING(for --enable-loadable-sqlite-extensions)
 AC_ARG_ENABLE(loadable-sqlite-extensions,

setup.py

@@ -1796,6 +1796,16 @@ class PyBuildExt(build_ext):
             self.use_system_libffi = True
 
     def _decimal_ext(self):
+        extra_compile_args = []
+        undef_macros=['NDEBUG']
+        if '--with-system-libmpdec' in sysconfig.get_config_var("CONFIG_ARGS"):
+            include_dirs = []
+            libraries = ['mpdec']
+            sources = ['_decimal/_decimal.c']
+            depends = ['_decimal/docstrings.h']
+        else:
+            include_dirs = ['./Modules/_decimal/libmpdec']
+            libraries = []
             sources = [
               '_decimal/_decimal.c',
               '_decimal/libmpdec/basearith.c',
@@ -1832,6 +1842,7 @@ class PyBuildExt(build_ext):
               '_decimal/libmpdec/typearith.h',
               '_decimal/libmpdec/umodarith.h',
               ]
+
         config = {
           'x64':     [('CONFIG_64','1'), ('ASM','1')],
           'uint128': [('CONFIG_64','1'), ('ANSI','1'), ('HAVE_UINT128_T','1')],
@@ -1843,10 +1854,6 @@ class PyBuildExt(build_ext):
           'universal':   [('UNIVERSAL','1')]
         }
 
-        include_dirs = ['./Modules/_decimal/libmpdec']
-        extra_compile_args = []
-        undef_macros=['NDEBUG']
-
         platform = self.get_platform()
         cc = sysconfig.get_config_var('CC')
         sizeof_size_t = sysconfig.get_config_var('SIZEOF_SIZE_T')
@@ -1898,6 +1905,7 @@ class PyBuildExt(build_ext):
         ext = Extension (
             '_decimal',
             include_dirs=include_dirs,
+            libraries=libraries,
             define_macros=define_macros,
             undef_macros=undef_macros,
             extra_compile_args=extra_compile_args,