diff --git a/sphinx_config.h.in b/sphinx_config.h.in
index 81b34863..3314ce1c 100644
--- a/sphinx_config.h.in
+++ b/sphinx_config.h.in
@@ -7,7 +7,9 @@
 #cmakedefine DEFAULT_RADIX @DEFAULT_RADIX@
 
 /* Define if you have the <stdint.h> header file. */
+#ifndef HAVE_STDINT_H
 #cmakedefine HAVE_STDINT_H
+#endif
 
 /* The size of `long', as computed by sizeof. */
 #cmakedefine SIZEOF_LONG @SIZEOF_LONG@