--- a/util/hb-info.cc
+++ b/util/hb-info.cc
@@ -35,6 +35,10 @@
 # include <chafa.h>
 #endif
 
+#ifdef environ
+#undef environ
+#endif
+
 const unsigned DEFAULT_FONT_SIZE = FONT_SIZE_UPEM;
 const unsigned SUBPIXEL_BITS = 0;
 
