diff --git a/aclocal.m4 b/aclocal.m4
index cee75981be..e64d57b758 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1,4 +1,4 @@
-# generated automatically by aclocal 1.9.3 -*- Autoconf -*-
+# generated automatically by aclocal 1.9.4 -*- Autoconf -*-
 
 # Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
 # Free Software Foundation, Inc.
@@ -328,8 +328,14 @@ AC_DEFUN([AC_BAKEFILE_PLATFORM_SPECIFICS],
       *-*-darwin* )
         dnl For Unix to MacOS X porting instructions, see:
         dnl http://fink.sourceforge.net/doc/porting/porting.html
-        CFLAGS="$CFLAGS -fno-common"
-        CXXFLAGS="$CXXFLAGS -fno-common"
+        if test "x$GCC" = "xyes"; then
+            CFLAGS="$CFLAGS -fno-common"
+            CXXFLAGS="$CXXFLAGS -fno-common"
+        fi
+        if test "x$XLCC" = "xyes"; then
+            CFLAGS="$CFLAGS -qnocommon"
+            CXXFLAGS="$CXXFLAGS -qnocommon"
+        fi
         ;;
 
       *-pc-os2_emx | *-pc-os2-emx )
@@ -542,7 +548,12 @@ AC_DEFUN([AC_BAKEFILE_SHARED_LD],
             SHARED_LD_MODULE_CXX="\${CXX} -bundle -single_module -headerpad_max_install_names -o"
         fi
 
-        PIC_FLAG="-dynamic -fPIC"
+        if test "x$GCC" == "xyes"; then
+            PIC_FLAG="-dynamic -fPIC"
+        fi
+        if test "x$XLCC" = "xyes"; then
+            PIC_FLAG="-dynamic -DPIC"
+        fi
       ;;
 
       *-*-aix* )