diff --git a/racket/src/configure b/racket/src/configure
index 7c820dfe87..dc8d3ba112 100755
--- a/racket/src/configure
+++ b/racket/src/configure
@@ -2584,7 +2584,7 @@ COMPFLAGS=""
 ORIG_CC="${CC}"
 ORIG_CPP="${CPP}"
 # Include `--enable-portable-binary' by default for libffi
-SUB_CONFIGURE_EXTRAS="--enable-portable-binary"
+SUB_CONFIGURE_EXTRAS=" --enable-portable-binary"
 
 if test "${enable_oskit}" = "no" ; then
   ac_ext=c
diff --git a/racket/src/racket/configure.ac b/racket/src/racket/configure.ac
index 5d05bcbcc4..219b1d58c1 100644
--- a/racket/src/racket/configure.ac
+++ b/racket/src/racket/configure.ac
@@ -464,7 +464,7 @@ COMPFLAGS=""
 ORIG_CC="${CC}"
 ORIG_CPP="${CPP}"
 # Include `--enable-portable-binary' by default for libffi
-SUB_CONFIGURE_EXTRAS="--enable-portable-binary"
+SUB_CONFIGURE_EXTRAS=" --enable-portable-binary"
 
 if test "${enable_oskit}" = "no" ; then
   AC_PROG_CC