Add DLR's excellent workaround for strcasecmp not being available

git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@1511 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

ChangeLog

@@ -8,6 +8,10 @@ CVS code -
   align()
 	- Tweak to avoid a potential problem when strp is non-NULL but
 	  *strp is NULL. (David Benbennick)
+  nstricmp(), nstrnicmp()
+	- Add these functions, equivalent to strcasecmp() and
+	  strncasecmp(), and convert nano to use them when strcasecmp()
+	  and/or strncasecmp() are unavailable. (DLR)
 - winio.c:
   do_help()
 	- Get rid of keypad_on() call for bottomwin, which should not be

nano.h

@@ -80,11 +80,11 @@
 #endif
 
 #ifndef HAVE_STRCASECMP
-#define strcasecmp strcmp
+#define strcasecmp nstricmp
 #endif
 
 #ifndef HAVE_STRNCASECMP
-#define strncasecmp strncmp
+#define strncasecmp nstrnicmp
 #endif
 
 /* HP-UX 10 & 11 do not seem to support KEY_HOME and KEY_END */

proto.h

@@ -399,6 +399,12 @@ void align(char **strp);
 void null_at(char **data, size_t index);
 void unsunder(char *str, size_t true_len);
 void sunder(char *str);
+#ifndef HAVE_STRCASECMP
+int nstricmp(const char *s1, const char *s2);
+#endif
+#ifndef HAVE_STRNCASECMP
+int nstrnicmp(const char *s1, const char *s2, size_t n);
+#endif
 #ifndef NANO_SMALL
 const char *revstrstr(const char *haystack, const char *needle,
 			const char *rev_start);

utils.c

@@ -99,6 +99,37 @@ void sunder(char *str)
 	    *str = '\0';
 }
 
+#ifndef HAVE_STRCASECMP
+/* This function is equivalent to strcasecmp(). */
+int nstricmp(const char *s1, const char *s2)
+{
+    assert(s1 != NULL && s2 != NULL);
+    for (; *s1 != '\0' && *s2 != '\0'; s1++, s2++) {
+	if (tolower(*s1) != tolower(*s2))
+	    break;
+    }
+    return (tolower(*s1) - tolower(*s2));
+}
+#endif
+
+#ifndef HAVE_STRNCASECMP
+/* This function is equivalent to strncasecmp(). */
+int nstrnicmp(const char *s1, const char *s2, size_t n)
+{
+    assert(s1 != NULL && s2 != NULL);
+    for (; n > 0 && *s1 != '\0' && *s2 != '\0'; n--, s1++, s2++) {
+	if (tolower(*s1) != tolower(*s2))
+	    break;
+    }
+    if (n > 0)
+	return (tolower(*s1) - tolower(*s2));
+    else if (n == 0)
+	return 0;
+    else if (n < 0)
+	return -1;
+}
+#endif
+
 /* None of this is needed if we're using NANO_SMALL! */
 #ifndef NANO_SMALL
 const char *revstrstr(const char *haystack, const char *needle,