diff --git a/erts/configure b/erts/configure
index 63d007b8d7b6..a4d5df1cb867 100755
--- a/erts/configure
+++ b/erts/configure
@@ -21733,6 +21733,7 @@ else case e in #(
 /* end confdefs.h.  */
 
 #include <stdlib.h>
+#include <unistd.h>
 #ifdef HAVE_MALLOC_H
 #  include <malloc.h>
 #endif
diff --git a/erts/configure.ac b/erts/configure.ac
index fa1bfe2a932d..4a05fadaa1da 100644
--- a/erts/configure.ac
+++ b/erts/configure.ac
@@ -2443,6 +2443,7 @@ AC_CACHE_CHECK([if __after_morecore_hook can track malloc()s core memory use],
 		erts_cv___after_morecore_hook_can_track_malloc,
 		[AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #include <stdlib.h>
+#include <unistd.h>
 #ifdef HAVE_MALLOC_H
 #  include <malloc.h>
 #endif