Set PYTHON*DYNAMICLINKING for AIX

Changes based on supplied patch, but reworked version not tested as
I don't have access to AIX and the submitter hasn't responded in
18 months.

Fixes #1920

configure.ac

@@ -779,6 +779,9 @@ else
     PYTHONDYNAMICLINKING="-L$PYLIB $PYLINK"
     DEFS="-DUSE_DL_IMPORT $DEFS"
     ;;
+  *-*-aix*)
+    PYTHONDYNAMICLINKING="-L$PYLIB $PYLINK"
+    ;;
   *)PYTHONDYNAMICLINKING="";;
   esac
 fi
@@ -954,6 +957,9 @@ else
     PYTHON3DYNAMICLINKING="-L$PY3LIB $PY3LINK"
     DEFS="-DUSE_DL_IMPORT $DEFS"
     ;;
+  *-*-aix*)
+    PYTHON3DYNAMICLINKING="-L$PY3LIB $PY3LINK"
+    ;;
   *)PYTHON3DYNAMICLINKING="";;
   esac