diff --git a/mercurial/osutil.c b/mercurial/osutil.c
--- a/mercurial/osutil.c
+++ b/mercurial/osutil.c
@@ -23,7 +23,7 @@
 # include <unistd.h>
 #endif
 
-// some platforms lack the PATH_MAX definition (eg. GNU/Hurd)
+/* some platforms lack the PATH_MAX definition (eg. GNU/Hurd) */
 #ifndef PATH_MAX
 #define PATH_MAX 4096
 #endif