diff --git a/configure.ac b/configure.ac
index 1808a643f3..c68b7632e6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3015,7 +3015,6 @@ STATIC=
                           # When building ext bundles, a mach-o bundle needs to know its loader
                           # program to bind symbols from the ruby executable
                           EXTDLDFLAGS="-bundle_loader '\$(BUILTRUBY)'"
-                          PREP="$PREP"' $(PROGRAM)'
 			])
 			rb_cv_dlopen=yes],
         [aix*], [	: ${LDSHARED='$(CC)'}
@@ -3340,7 +3339,7 @@ AS_IF([test x"$cross_compiling" = xyes], [
   AC_SUBST(XRUBY_LIBDIR)
   AC_SUBST(XRUBY_RUBYLIBDIR)
   AC_SUBST(XRUBY_RUBYHDRDIR)
-  PREP="$PREP "'$(arch)-fake.rb'
+  PREP='$(arch)-fake.rb'
   RUNRUBY_COMMAND='$(MINIRUBY) -I`cd $(srcdir)/lib; pwd`'
   RUNRUBY='$(RUNRUBY_COMMAND)'
   XRUBY='$(MINIRUBY)'
@@ -3350,7 +3349,7 @@ AS_IF([test x"$cross_compiling" = xyes], [
 ], [
   MINIRUBY='./miniruby$(EXEEXT) -I$(srcdir)/lib -I.'
   MINIRUBY="$MINIRUBY"' -I$(EXTOUT)/common'
-  PREP="$PREP "'miniruby$(EXEEXT)'
+  PREP='miniruby$(EXEEXT)'
   RUNRUBY_COMMAND='$(MINIRUBY) $(tooldir)/runruby.rb --extout=$(EXTOUT) $(RUNRUBYOPT)'
   RUNRUBY='$(RUNRUBY_COMMAND) --'
   XRUBY='$(RUNRUBY)'
diff --git a/enc/Makefile.in b/enc/Makefile.in
index 0e1a27a667..dd8ca1b528 100644
--- a/enc/Makefile.in
+++ b/enc/Makefile.in
@@ -36,7 +36,7 @@ RUBY_SO_NAME = @RUBY_SO_NAME@
 LIBRUBY = @LIBRUBY@
 LIBRUBYARG_SHARED = @LIBRUBYARG_SHARED@
 LIBRUBYARG_STATIC = $(LIBRUBYARG_SHARED)
-BUILTRUBY = $(topdir)/ruby$(EXEEXT)
+BUILTRUBY = $(topdir)/miniruby$(EXEEXT)
 
 empty =
 AR = @AR@
diff --git a/ext/extmk.rb b/ext/extmk.rb
index b0d84ef00f..1624ec9099 100755
--- a/ext/extmk.rb
+++ b/ext/extmk.rb
@@ -427,7 +427,7 @@ end
 topruby = $ruby
 $ruby = topruby.join(' ')
 $mflags << "ruby=#$ruby"
-$builtruby = '$(topdir)/ruby' + EXEEXT # Must be an executable path
+$builtruby = '$(topdir)/miniruby' + EXEEXT # Must be an executable path
 
 MTIMES = [__FILE__, 'rbconfig.rb', srcdir+'/lib/mkmf.rb'].collect {|f| File.mtime(f)}