diff -ruNa zeromq-4.0.4_org/tools/Makefile.am zeromq-4.0.4/tools/Makefile.am
--- zeromq-4.0.4_org/tools/Makefile.am	2014-06-03 20:01:12.392379933 +0800
+++ zeromq-4.0.4/tools/Makefile.am	2014-06-03 19:59:18.616382420 +0800
@@ -1,5 +1,5 @@
 EXTRA_DIST = curve_keygen.c 
+CFLAGS += -std=c99
-
 INCLUDES = -I$(top_srcdir)/include
 
 bin_PROGRAMS = curve_keygen
