diff --git a/libsigrok4DSL/configure.ac b/libsigrok4DSL/configure.ac
index 1b00cca8..a413d6eb 100644
--- a/libsigrok4DSL/configure.ac
+++ b/libsigrok4DSL/configure.ac
@@ -48,6 +48,7 @@ CFLAGS="$CFLAGS -Wall -Wextra -fvisibility=hidden -ludev -Wl,--rpath=/usr/local/
 
 # Checks for programs.
 AC_PROG_CC
+AC_PROG_CC_STDC
 AC_PROG_CPP
 AC_PROG_INSTALL
 AC_PROG_LN_S