diff --git a/gdbsupport/ChangeLog b/gdbsupport/ChangeLog
index cf275a49947..dfbb06e61b6 100644
--- a/gdbsupport/ChangeLog
+++ b/gdbsupport/ChangeLog
@@ -1,3 +1,7 @@
+2021-04-23  Simon Marchi  <simon.marchi@polymtl.ca>
+
+	* common-debug.h: Include preprocessor.h.
+
 2021-03-24  Luis Machado  <luis.machado@linaro.org>
 
 	* rsp-low.cc (fromhex, hex2bin): Move to ...
diff --git a/gdbsupport/common-debug.h b/gdbsupport/common-debug.h
index 05367401a7d..7288b694d59 100644
--- a/gdbsupport/common-debug.h
+++ b/gdbsupport/common-debug.h
@@ -20,6 +20,8 @@
 #ifndef COMMON_COMMON_DEBUG_H
 #define COMMON_COMMON_DEBUG_H
 
+#include "gdbsupport/preprocessor.h"
+
 /* Set to true to enable debugging of hardware breakpoint/
    watchpoint support code.  */