diff --git a/configure b/configure
index 126fee3d2..6fc612b58 100755
--- a/configure
+++ b/configure
@@ -21,7 +21,7 @@ EXCERTS="yes"
 PRNG=
 PRNGLIBS=
 
-CFLAGS="-fPIC -Wall -pedantic -std=c89"
+CFLAGS="-fPIC -Wall -pedantic -std=c99"
 LDFLAGS="-shared"
 
 IDN_LIBRARY="idn"