--- dash-0.5.10.2/src/system.c.orig	Sun May 10 01:45:02 2020
+++ dash-0.5.10.2/src/system.c	Sun May 10 01:50:52 2020
@@ -131,64 +131,64 @@
 
 #ifndef HAVE_ISALPHA
 int isalnum(int c) {
-	return _isalnum(c);
+	return (_ctype_[(int)(c)] & (_U | _L | _N));
 }
 
 
 int iscntrl(int c) {
-	return _iscntrl(c);
+	return (_ctype_[(int)(c)] & (_C));
 }
 
 
 int islower(int c) {
-	return _islower(c);
+	return ((_ctype_[(int)(c)] & (_U | _L)) == _L);
 }
 
 
 int isspace(int c) {
-	return _isspace(c);
+	return (_ctype_[(int)(c)] & (_S));
 }
 
 
 int isalpha(int c) {
-	return _isalpha(c);
+	return (_ctype_[(int)(c)] & (_U | _L));
 }
 
 
 int isdigit(int c) {
-	return _isdigit(c);
+	return (_ctype_[(int)(c)] & (_N));
 }
 
 
 int isprint(int c) {
-	return _isprint(c);
+	return (_ctype_[(int)(c)] & (_P | _U | _L | _N | _B));
 }
 
 
 int isupper(int c) {
-	return _isupper(c);
+	return ((_ctype_[(int)(c)] & (_U | _L)) == _U);
 }
 
 
 #if HAVE_DECL_ISBLANK
 int isblank(int c) {
-	return _isblank(c);
+	return (c == ' ' || c == '\t');
 }
 #endif
 
 
 int isgraph(int c) {
-	return _isgraph(c);
+	return (_ctype_[(int)(c)] & (_P | _U | _L | _N));
 }
 
 
 int ispunct(int c) {
-	return _ispunct(c);
+	return (_ctype_[(int)(c)] & (_P));
 }
 
 
 int isxdigit(int c) {
-	return _isxdigit(c);
+	return (_ctype_[(int)(c)] & (_N | _X));
 }
 #endif