diff -up libdap-3.13.1/unit-tests/DDSTest.cc.getopt libdap-3.13.1/unit-tests/DDSTest.cc
--- libdap-3.13.1/unit-tests/DDSTest.cc.getopt	2014-02-04 15:30:33.000000000 -0700
+++ libdap-3.13.1/unit-tests/DDSTest.cc	2014-07-15 10:41:17.078813570 -0600
@@ -496,7 +496,7 @@ int main(int argc, char*argv[]) {
     runner.addTest(CppUnit::TestFactoryRegistry::getRegistry().makeTest());
 
     GetOpt getopt(argc, argv, "d");
-    char option_char;
+    int option_char;
     while ((option_char = getopt()) != EOF)
         switch (option_char) {
         case 'd':
diff -up libdap-3.13.1/unit-tests/DDXParserTest.cc.getopt libdap-3.13.1/unit-tests/DDXParserTest.cc
--- libdap-3.13.1/unit-tests/DDXParserTest.cc.getopt	2014-02-04 16:15:11.000000000 -0700
+++ libdap-3.13.1/unit-tests/DDXParserTest.cc	2014-07-15 10:35:11.120617282 -0600
@@ -652,7 +652,7 @@ int main(int argc, char*argv[])
 	runner.addTest(CppUnit::TestFactoryRegistry::getRegistry().makeTest());
 
 	GetOpt getopt(argc, argv, "d");
-	char option_char;
+	int option_char;
 	while ((option_char = getopt()) != EOF)
 		switch (option_char) {
 		case 'd':
diff -up libdap-3.13.1/unit-tests/SequenceTest.cc.getopt libdap-3.13.1/unit-tests/SequenceTest.cc
--- libdap-3.13.1/unit-tests/SequenceTest.cc.getopt	2014-07-15 10:42:22.638487942 -0600
+++ libdap-3.13.1/unit-tests/SequenceTest.cc	2014-07-15 10:42:33.222434496 -0600
@@ -432,7 +432,7 @@ int main(int argc, char*argv[]) {
     runner.addTest(CppUnit::TestFactoryRegistry::getRegistry().makeTest());
 
     GetOpt getopt(argc, argv, "d");
-    char option_char;
+    int option_char;
     while ((option_char = getopt()) != EOF)
         switch (option_char) {
         case 'd':
diff -up libdap-3.13.1/unit-tests/ServerFunctionsListUnitTest.cc.getopt libdap-3.13.1/unit-tests/ServerFunctionsListUnitTest.cc
--- libdap-3.13.1/unit-tests/ServerFunctionsListUnitTest.cc.getopt	2013-10-01 10:05:23.000000000 -0600
+++ libdap-3.13.1/unit-tests/ServerFunctionsListUnitTest.cc	2014-07-15 10:41:40.310697732 -0600
@@ -183,7 +183,7 @@ int main(int argc, char*argv[]) {
     runner.addTest(CppUnit::TestFactoryRegistry::getRegistry().makeTest());
 
     GetOpt getopt(argc, argv, "d");
-    char option_char;
+    int option_char;
     while ((option_char = getopt()) != EOF)
         switch (option_char) {
         case 'd':