diff --git a/configure.ac b/configure.ac
index 0936760..ce8feb7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6,8 +6,6 @@ AC_CONFIG_AUX_DIR([ac])
 AM_INIT_AUTOMAKE([subdir-objects -Wall -Wno-portability foreign])
 AM_SILENT_RULES([yes])
 
-# Without this line, AC_PROG_CC boneheadedly adds `-g -O2` to our CFLAGS.
-AC_SUBST(CFLAGS, "")
 AC_PROG_CC
 AC_USE_SYSTEM_EXTENSIONS