diff --git a/general.h b/general.h
index 91425b8c..8471a347 100644
--- a/general.h
+++ b/general.h
@@ -110,8 +110,13 @@ extern char *strcpy (char *, const char *);
 #define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)
 
 /* Define exactly what a legal shell identifier consists of. */
-#define legal_variable_starter(c) (ISALPHA(c) || (c == '_'))
-#define legal_variable_char(c)	(ISALNUM(c) || c == '_')
+#if 0
+#define legal_variable_starter(c) (c < 128 && (ISALPHA(c) || c == '_'))
+#define legal_variable_char(c)	(c < 128 && (ISALNUM(c) || c == '_'))
+#else
+#define legal_variable_starter(c) (sh_syntaxtab[c] & CNAMESTART)
+#define legal_variable_char(c)	(sh_syntaxtab[c] & CNAME)
+#endif
 
 /* Definitions used in subst.c and by the `read' builtin for field
    splitting. */
diff --git a/mksyntax.c b/mksyntax.c
index 5a64c8f5..66fbbfdf 100644
--- a/mksyntax.c
+++ b/mksyntax.c
@@ -60,6 +60,8 @@ struct wordflag {
 	{ CSPECVAR,	"CSPECVAR" },
 	{ CSUBSTOP,	"CSUBSTOP" },
 	{ CBLANK,	"CBLANK" },
+	{ CNAME,	"CNAME" },
+	{ CNAMESTART,	"CNAMESTART" }
 };
 	
 #define N_WFLAGS	(sizeof (wordflags) / sizeof (wordflags[0]))
@@ -198,6 +200,45 @@ addblanks (void)
     }
 }
 
+static void
+setnamechars(void)
+{
+  lsyntax['_'] |= CNAME|CNAMESTART;
+
+  lsyntax['0'] |= CNAME; lsyntax['1'] |= CNAME; lsyntax['2'] |= CNAME;
+  lsyntax['3'] |= CNAME; lsyntax['4'] |= CNAME; lsyntax['5'] |= CNAME;
+  lsyntax['6'] |= CNAME; lsyntax['7'] |= CNAME; lsyntax['8'] |= CNAME;
+  lsyntax['9'] |= CNAME;
+
+  lsyntax['a'] |= CNAME|CNAMESTART; lsyntax['b'] |= CNAME|CNAMESTART;
+  lsyntax['c'] |= CNAME|CNAMESTART; lsyntax['d'] |= CNAME|CNAMESTART;
+  lsyntax['e'] |= CNAME|CNAMESTART; lsyntax['f'] |= CNAME|CNAMESTART;
+  lsyntax['g'] |= CNAME|CNAMESTART; lsyntax['h'] |= CNAME|CNAMESTART;
+  lsyntax['i'] |= CNAME|CNAMESTART; lsyntax['j'] |= CNAME|CNAMESTART;
+  lsyntax['k'] |= CNAME|CNAMESTART; lsyntax['l'] |= CNAME|CNAMESTART;
+  lsyntax['m'] |= CNAME|CNAMESTART; lsyntax['n'] |= CNAME|CNAMESTART;
+  lsyntax['o'] |= CNAME|CNAMESTART; lsyntax['p'] |= CNAME|CNAMESTART;
+  lsyntax['q'] |= CNAME|CNAMESTART; lsyntax['r'] |= CNAME|CNAMESTART;
+  lsyntax['s'] |= CNAME|CNAMESTART; lsyntax['t'] |= CNAME|CNAMESTART;
+  lsyntax['u'] |= CNAME|CNAMESTART; lsyntax['v'] |= CNAME|CNAMESTART;
+  lsyntax['w'] |= CNAME|CNAMESTART; lsyntax['x'] |= CNAME|CNAMESTART;
+  lsyntax['y'] |= CNAME|CNAMESTART; lsyntax['z'] |= CNAME|CNAMESTART;
+
+  lsyntax['A'] |= CNAME|CNAMESTART; lsyntax['B'] |= CNAME|CNAMESTART;
+  lsyntax['C'] |= CNAME|CNAMESTART; lsyntax['D'] |= CNAME|CNAMESTART;
+  lsyntax['E'] |= CNAME|CNAMESTART; lsyntax['F'] |= CNAME|CNAMESTART;
+  lsyntax['G'] |= CNAME|CNAMESTART; lsyntax['H'] |= CNAME|CNAMESTART;
+  lsyntax['I'] |= CNAME|CNAMESTART; lsyntax['J'] |= CNAME|CNAMESTART;
+  lsyntax['K'] |= CNAME|CNAMESTART; lsyntax['L'] |= CNAME|CNAMESTART;
+  lsyntax['M'] |= CNAME|CNAMESTART; lsyntax['N'] |= CNAME|CNAMESTART;
+  lsyntax['O'] |= CNAME|CNAMESTART; lsyntax['P'] |= CNAME|CNAMESTART;
+  lsyntax['Q'] |= CNAME|CNAMESTART; lsyntax['R'] |= CNAME|CNAMESTART;
+  lsyntax['S'] |= CNAME|CNAMESTART; lsyntax['T'] |= CNAME|CNAMESTART;
+  lsyntax['U'] |= CNAME|CNAMESTART; lsyntax['V'] |= CNAME|CNAMESTART;
+  lsyntax['W'] |= CNAME|CNAMESTART; lsyntax['X'] |= CNAME|CNAMESTART;
+  lsyntax['Y'] |= CNAME|CNAMESTART; lsyntax['Z'] |= CNAME|CNAMESTART;
+}
+
 /* load up the correct flag values in lsyntax */
 static void
 load_lsyntax (void)
@@ -234,6 +275,8 @@ load_lsyntax (void)
   addcstr ("-=?+", CSUBSTOP);		/* OP in ${paramOPword} */
 
   addblanks ();
+
+  setnamechars ();
 }
 
 static void
diff --git a/patchlevel.h b/patchlevel.h
index cc9a38f3..b8b6a783 100644
--- a/patchlevel.h
+++ b/patchlevel.h
@@ -25,6 +25,6 @@
    regexp `^#define[ 	]*PATCHLEVEL', since that's what support/mkversion.sh
    looks for to find the patch level (for the sccs version string). */
 
-#define PATCHLEVEL 18
+#define PATCHLEVEL 19
 
 #endif /* _PATCHLEVEL_H_ */
diff --git a/syntax.h b/syntax.h
index 34f54964..eb6f467b 100644
--- a/syntax.h
+++ b/syntax.h
@@ -63,6 +63,8 @@
 #define CSPECVAR	0x0800	/* single-character shell variable name */
 #define CSUBSTOP	0x1000	/* values of OP for ${word[:]OPstuff} */
 #define CBLANK		0x2000	/* whitespace (blank) character */
+#define CNAME		0x4000	/* POSIX name character ([_0-9a-zA-Z]) */
+#define CNAMESTART	0x8000	/* POSIX name start character ([_a-zA-Z]) */
 
 /* Defines for use by the rest of the shell. */
 extern int sh_syntaxtab[];