--- a/js/src/old-configure.in
+++ b/js/src/old-configure.in
@@ -685,22 +685,17 @@ case "$target" in
         PKG_SKIP_STRIP=1
         OBJ_SUFFIX=obj
         LIB_SUFFIX=lib
         DLL_PREFIX=
         LIB_PREFIX=
         IMPORT_LIB_SUFFIX=lib
         MKSHLIB='$(LINK) -NOLOGO -DLL -OUT:$@ -PDB:$(LINK_PDBFILE) $(DSO_LDOPTS)'
         MKCSHLIB='$(LINK) -NOLOGO -DLL -OUT:$@ -PDB:$(LINK_PDBFILE) $(DSO_LDOPTS)'
-        dnl Set subsystem version 5 for Windows XP.
-        if test "$CPU_ARCH" = "x86"; then
-            WIN32_SUBSYSTEM_VERSION=5.01
-        else
-            WIN32_SUBSYSTEM_VERSION=6.01
-        fi
+        WIN32_SUBSYSTEM_VERSION=6.01
         WIN32_CONSOLE_EXE_LDFLAGS=-SUBSYSTEM:CONSOLE,$WIN32_SUBSYSTEM_VERSION
         WIN32_GUI_EXE_LDFLAGS=-SUBSYSTEM:WINDOWS,$WIN32_SUBSYSTEM_VERSION
         DSO_LDOPTS=-SUBSYSTEM:WINDOWS,$WIN32_SUBSYSTEM_VERSION
         _USE_CPP_INCLUDE_FLAG=1
         _DEFINES_CFLAGS='-FI $(topobjdir)/js/src/js-confdefs.h -DMOZILLA_CLIENT'
         _DEFINES_CXXFLAGS='-FI $(topobjdir)/js/src/js-confdefs.h -DMOZILLA_CLIENT'
         CFLAGS="$CFLAGS -W3 -Gy -Zc:inline"
         CXXFLAGS="$CXXFLAGS -W3 -Gy -Zc:inline"

--- a/old-configure.in
+++ b/old-configure.in
@@ -974,22 +974,17 @@ case "$target" in
         PKG_SKIP_STRIP=1
         OBJ_SUFFIX=obj
         LIB_SUFFIX=lib
         DLL_PREFIX=
         LIB_PREFIX=
         IMPORT_LIB_SUFFIX=lib
         MKSHLIB='$(LINK) -NOLOGO -DLL -OUT:$@ -PDB:$(LINK_PDBFILE) $(DSO_LDOPTS)'
         MKCSHLIB='$(LINK) -NOLOGO -DLL -OUT:$@ -PDB:$(LINK_PDBFILE) $(DSO_LDOPTS)'
-        dnl Set subsystem version 5 for Windows XP.
-        if test "$CPU_ARCH" = "x86"; then
-            WIN32_SUBSYSTEM_VERSION=5.01
-        else
-            WIN32_SUBSYSTEM_VERSION=6.01
-        fi
+        WIN32_SUBSYSTEM_VERSION=6.01
         WIN32_CONSOLE_EXE_LDFLAGS=-SUBSYSTEM:CONSOLE,$WIN32_SUBSYSTEM_VERSION
         WIN32_GUI_EXE_LDFLAGS=-SUBSYSTEM:WINDOWS,$WIN32_SUBSYSTEM_VERSION
         DSO_LDOPTS=-SUBSYSTEM:WINDOWS,$WIN32_SUBSYSTEM_VERSION
         _USE_CPP_INCLUDE_FLAG=1
         _DEFINES_CFLAGS='-FI $(topobjdir)/mozilla-config.h -DMOZILLA_CLIENT'
         _DEFINES_CXXFLAGS='-FI $(topobjdir)/mozilla-config.h -DMOZILLA_CLIENT'
         CFLAGS="$CFLAGS -W3 -Gy -Zc:inline"
         CXXFLAGS="$CXXFLAGS -W3 -Gy -Zc:inline"