Use EXIT_SUCCESS and EXIT_FAILURE more consistently.

plugins/sudoers/regress/check_symbols/check_symbols.c

@@ -41,7 +41,7 @@ static void
 usage(void)
 {
     fprintf(stderr, "usage: %s plugin.so symbols_file\n", getprogname());
-    exit(1);
+    exit(EXIT_FAILURE);
 }
 
 int

plugins/sudoers/regress/env_match/check_env_pattern.c

@@ -46,7 +46,7 @@ main(int argc, char *argv[])
     if (argc > 1) {
 	if ((fp = fopen(argv[1], "r")) == NULL) {
 	    perror(argv[1]);
-	    exit(1);
+	    exit(EXIT_FAILURE);
 	}
     }
 

plugins/sudoers/regress/iolog_plugin/check_iolog_plugin.c

@@ -52,7 +52,7 @@ static void
 usage(void)
 {
     fprintf(stderr, "usage: %s pathname\n", getprogname());
-    exit(1);
+    exit(EXIT_FAILURE);
 }
 
 static int

plugins/sudoers/regress/logging/check_wrap.c

@@ -44,7 +44,7 @@ static void
 usage(void)
 {
     fprintf(stderr, "usage: %s inputfile\n", getprogname());
-    exit(1);
+    exit(EXIT_FAILURE);
 }
 
 int

plugins/sudoers/regress/parser/check_addr.c

@@ -77,7 +77,7 @@ static void
 usage(void)
 {
     fprintf(stderr, "usage: %s datafile\n", getprogname());
-    exit(1);
+    exit(EXIT_FAILURE);
 }
 
 int