diff --git a/tools/binpac/lib/binpac.h.in b/tools/binpac/lib/binpac.h.in
index f5c6e152c7..4e78b7b830 100644
--- a/tools/binpac/lib/binpac.h.in
+++ b/tools/binpac/lib/binpac.h.in
@@ -17,6 +17,13 @@
 #include <stdio.h>
 #include <string>
 #include <memory>
+
+// Expose C99 functionality from inttypes.h, which would otherwise not be
+// available in C++.
+#ifndef __STDC_FORMAT_MACROS
+#define __STDC_FORMAT_MACROS
+#endif
+
 #include <inttypes.h>
 
 #define BINPAC_ASSERT(x)	assert(x)