Avoid using cut; sed can do this just as well...
diff --git a/Makefile.in b/Makefile.in
index 8b2c979..f4f80ae 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -389,7 +389,7 @@
$(INSTALL_PROGRAM) $(srcdir)/install-sh $(LIBPL)/install-sh
$(INSTALL_DATA) $(srcdir)/Misc/Makefile.pre.in $(LIBPL)/Makefile.pre.in
@if [ -s Modules/python.exp -a \
- "`echo $(MACHDEP) | cut -c 1-3`" = "aix" ]; then \
+ "`echo $(MACHDEP) | sed 's/^\(...\).*/\1/'`" = "aix" ]; then \
echo; echo "Installing support files for building shared extension modules on AIX:"; \
$(INSTALL_DATA) Modules/python.exp \
$(LIBPL)/python.exp; \