Explicitly cast chars to unsigned chars for <ctype.h> functions

Apply the semantic patch to catch all the places where we pass 'char' to
the <ctype.h> family of functions (isalpha() and friends, toupper(),
tolower()).

(cherry picked from commit 29caa6d1f0)

contrib/dlz/modules/common/dlz_dbi.c

@@ -474,7 +474,7 @@ get_parameter_value(const char *input, const char *key) {
 
 	for (i = 0; i < 255; i++) {
 		value[i] = keystart[keylen + i];
-		if (isspace(value[i]) || value[i] == '\0') {
+		if (isspace((unsigned char)value[i]) || value[i] == '\0') {
 			value[i] = '\0';
 			break;
 		}

lib/dns/rdata.c

@@ -2057,7 +2057,7 @@ decvalue(char value) {
 	 * isascii() is valid for full range of int values, no need to
 	 * mask or cast.
 	 */
-	if (!isascii(value)) {
+	if (!isascii((unsigned char)value)) {
 		return (-1);
 	}
 	if ((s = strchr(decdigits, value)) == NULL) {

lib/isc/win32/file.c

@@ -569,10 +569,14 @@ isc_file_isabsolute(const char *filename) {
 	if ((filename[0] == '\\') && (filename[1] == '\\')) {
 		return (true);
 	}
-	if (isalpha(filename[0]) && filename[1] == ':' && filename[2] == '\\') {
+	if (isalpha((unsigned char)filename[0]) && filename[1] == ':' &&
+	    filename[2] == '\\')
+	{
 		return (true);
 	}
-	if (isalpha(filename[0]) && filename[1] == ':' && filename[2] == '/') {
+	if (isalpha((unsigned char)filename[0]) && filename[1] == ':' &&
+	    filename[2] == '/')
+	{
 		return (true);
 	}
 	return (false);

lib/isc/win32/fsaccess.c

@@ -70,7 +70,7 @@ is_ntfs(const char *file) {
 	 * Look for c:\path\... style, c:/path/... or \\computer\shar\path...
 	 * the UNC style file specs
 	 */
-	if (isalpha(filename[0]) && filename[1] == ':' &&
+	if (isalpha((unsigned char)filename[0]) && filename[1] == ':' &&
 	    (filename[2] == '\\' || filename[2] == '/'))
 	{
 		/* Copy 'c:\' or 'c:/' and NUL terminate. */