diff --git a/libgo/Makefile.am b/libgo/Makefile.am
index 88ea272..1112ee2 100644
--- a/libgo/Makefile.am
+++ b/libgo/Makefile.am
@@ -1244,8 +1244,15 @@
 all-local: $(ALL_LOCAL_DEPS)
 
 MAJOR=$(firstword $(subst :, ,$(libtool_VERSION)))
+
+# If we want to use "AR -r" when creating AIX FAT archives,
+# AR must be stripped of all its -X flags.
+# Otherwize, if AR was defined with -X32_64, the replace option would
+# erase the default .so when adding the extra one. There is no
+# order priority within -X flags.
 add-aix-fat-library: all-multi
 	@if test "$(MULTIBUILDTOP)" = ""; then \
-	  ${AR} -X$(AIX_DEFAULT_ARCH) rc .libs/$(PACKAGE).a ../ppc$(AIX_DEFAULT_ARCH)/$(PACKAGE)/.libs/$(PACKAGE).so.$(MAJOR); \
-	  ${AR} -X$(AIX_DEFAULT_ARCH) rc ../pthread/$(PACKAGE)/.libs/$(PACKAGE).a ../pthread/ppc$(AIX_DEFAULT_ARCH)/$(PACKAGE)/.libs/$(PACKAGE).so.$(MAJOR); \
+	  arx=`echo $(AR) | sed -e 's/-X[^ ]*//g'`; \
+	  $${arx} -X$(AIX_EXTRA_ARCH) rc .libs/$(PACKAGE).a ../ppc$(AIX_EXTRA_ARCH)/$(PACKAGE)/.libs/$(PACKAGE).so.$(MAJOR); \
+	  $${arx} -X$(AIX_EXTRA_ARCH) rc ../pthread/$(PACKAGE)/.libs/$(PACKAGE).a ../pthread/ppc$(AIX_EXTRA_ARCH)/$(PACKAGE)/.libs/$(PACKAGE).so.$(MAJOR); \
 	fi
diff --git a/libgo/Makefile.in b/libgo/Makefile.in
index 4aa9e98..1fb8da6 100644
--- a/libgo/Makefile.in
+++ b/libgo/Makefile.in
@@ -380,7 +380,7 @@
 CSCOPE = cscope
 DIST_SUBDIRS = testsuite
 ACLOCAL = @ACLOCAL@
-AIX_DEFAULT_ARCH = @AIX_DEFAULT_ARCH@
+AIX_EXTRA_ARCH = @AIX_EXTRA_ARCH@
 ALLGOARCH = @ALLGOARCH@
 ALLGOARCHFAMILY = @ALLGOARCHFAMILY@
 ALLGOOS = @ALLGOOS@
@@ -3118,10 +3118,17 @@
 distclean-local: distclean-multi
 maintainer-clean-local: maintainer-clean-multi
 all-local: $(ALL_LOCAL_DEPS)
+
+# If we want to use "AR -r" when creating AIX FAT archives,
+# AR must be stripped of all its -X flags.
+# Otherwize, if AR was defined with -X32_64, the replace option would
+# erase the default .so when adding the extra one. There is no
+# order priority within -X flags.
 add-aix-fat-library: all-multi
 	@if test "$(MULTIBUILDTOP)" = ""; then \
-	  ${AR} -X$(AIX_DEFAULT_ARCH) rc .libs/$(PACKAGE).a ../ppc$(AIX_DEFAULT_ARCH)/$(PACKAGE)/.libs/$(PACKAGE).so.$(MAJOR); \
-	  ${AR} -X$(AIX_DEFAULT_ARCH) rc ../pthread/$(PACKAGE)/.libs/$(PACKAGE).a ../pthread/ppc$(AIX_DEFAULT_ARCH)/$(PACKAGE)/.libs/$(PACKAGE).so.$(MAJOR); \
+	  arx=`echo $(AR) | sed -e 's/-X[^ ]*//g'`; \
+	  $${arx} -X$(AIX_EXTRA_ARCH) rc .libs/$(PACKAGE).a ../ppc$(AIX_EXTRA_ARCH)/$(PACKAGE)/.libs/$(PACKAGE).so.$(MAJOR); \
+	  $${arx} -X$(AIX_EXTRA_ARCH) rc ../pthread/$(PACKAGE)/.libs/$(PACKAGE).a ../pthread/ppc$(AIX_EXTRA_ARCH)/$(PACKAGE)/.libs/$(PACKAGE).so.$(MAJOR); \
 	fi
 
 # Tell versions [3.59,3.63) of GNU make to not export all variables.
diff --git a/libgo/configure b/libgo/configure
index 74bf072..7be9571 100755
--- a/libgo/configure
+++ b/libgo/configure
@@ -733,7 +733,7 @@
 MAINT
 MAINTAINER_MODE_FALSE
 MAINTAINER_MODE_TRUE
-AIX_DEFAULT_ARCH
+AIX_EXTRA_ARCH
 am__fastdepCCAS_FALSE
 am__fastdepCCAS_TRUE
 CCASDEPMODE
@@ -4716,10 +4716,10 @@
     GOCFLAGS="$GOCFLAGS -fno-section-anchors"
 
     # Check default architecture for FAT library creation
-    if test -z "`$(CC) -x c -E /dev/null -g3 -o - | grep 64BIT`" ; then
-        AIX_DEFAULT_ARCH='64'
+    if test -z "`$CC -x c -E /dev/null -g3 -o - | grep 64BIT`" ; then
+        AIX_EXTRA_ARCH='64'
     else
-        AIX_DEFAULT_ARCH='32'
+        AIX_EXTRA_ARCH='32'
     fi
 
     ;;
diff --git a/libgo/configure.ac b/libgo/configure.ac
index db5848e..abc58b8 100644
--- a/libgo/configure.ac
+++ b/libgo/configure.ac
@@ -38,12 +38,12 @@
     GOCFLAGS="$GOCFLAGS -fno-section-anchors"
 
     # Check default architecture for FAT library creation
-    if test -z "`$(CC) -x c -E /dev/null -g3 -o - | grep 64BIT`" ; then
-        AIX_DEFAULT_ARCH='64'
+    if test -z "`$CC -x c -E /dev/null -g3 -o - | grep 64BIT`" ; then
+        AIX_EXTRA_ARCH='64'
     else
-        AIX_DEFAULT_ARCH='32'
+        AIX_EXTRA_ARCH='32'
     fi
-    AC_SUBST(AIX_DEFAULT_ARCH)
+    AC_SUBST(AIX_EXTRA_ARCH)
     ;;
 esac
 
diff --git a/libgo/testsuite/Makefile.in b/libgo/testsuite/Makefile.in
index ae42fad..7869265 100644
--- a/libgo/testsuite/Makefile.in
+++ b/libgo/testsuite/Makefile.in
@@ -131,7 +131,7 @@
 DEJATOOL = $(PACKAGE)
 RUNTESTDEFAULTFLAGS = --tool $$tool --srcdir $$srcdir
 ACLOCAL = @ACLOCAL@
-AIX_DEFAULT_ARCH = @AIX_DEFAULT_ARCH@
+AIX_EXTRA_ARCH = @AIX_EXTRA_ARCH@
 ALLGOARCH = @ALLGOARCH@
 ALLGOARCHFAMILY = @ALLGOARCHFAMILY@
 ALLGOOS = @ALLGOOS@