diff --git a/configure.in b/configure.in
index d8da057..a0ea301 100644
--- a/configure.in
+++ b/configure.in
@@ -138,9 +138,9 @@
 SAVE_CFLAGS="$CFLAGS"
 CFLAGS='-I./include -I $(top_srcdir)/include -Wall -W'
 if test x$debug = xtrue; then
-CFLAGS="$CFLAGS -g -O0 -DDEBUG"
+	CFLAGS="$CFLAGS -g -O0 -DDEBUG"
 else
-CFLAGS="$CFLAGS -O3 -DNDEBUG"
+	CFLAGS="$CFLAGS -O3 -DNDEBUG"
 	if test x$GCC = xyes; then
 		CFLAGS="$CFLAGS -fomit-frame-pointer -funroll-loops -finline-functions -Winline -DFLAC__INLINE=__inline__"
 	fi