Add unsetenv to libroken.

Fix telnet(d) to link with libroken.


git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@455 ec53bebd-3082-4978-b11e-865c3cabbd6b

lib/roken/unsetenv.c

@@ -0,0 +1,35 @@
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdlib.h>
+
+RCSID("$Id$");
+
+extern char **environ;
+
+/*
+ * unsetenv --
+ */
+void
+unsetenv(const char *name)
+{
+  int len;
+  const char *np;
+  char **p;
+
+  if (name == 0 || environ == 0)
+    return;
+
+  for (np = name; *np && *np != '='; np++)
+    /* nop */;
+  len = np - name;
+  
+  for (p = environ; *p != 0; p++)
+    if (strncmp(*p, name, len) == 0 && (*p)[len] == '=')
+      break;
+
+  for (; *p != 0; p++)
+    *p = *(p + 1);
+}
+