Use special values SIGCONT_FG and SIGCONT_BG instead of SIGUSR1 and

SIGUSR2 to indicate whether the child should be continued in the
foreground or background.

src/sudo_exec.h

@@ -17,6 +17,12 @@
 #ifndef _SUDO_EXEC_H
 #define _SUDO_EXEC_H
 
+/*
+ * Special values to indicate whether continuing in foreground or background.
+ */
+#define SIGCONT_FG	-2
+#define SIGCONT_BG	-3
+
 /*
  * Symbols shared between exec.c and exec_pty.c
  */