Fixed some Nyquist bugs, eliminate some compiler and wipro checker warnings

lib-src/libnyquist/nyquist/xlisp/xlsys.c

@@ -4,6 +4,9 @@
         Permission is granted for unrestricted non-commercial use	*/
 
 /* HISTORY
+ *
+ * 11-Dec-09    Roger Dannenberg
+ *  Added getenv
  *
  * 28-Apr-03	Dominic Mazzoni
  *  Eliminated some compiler warnings
@@ -49,6 +52,20 @@ extern LVAL s_true;
 extern FILE *osaopen();
 extern LVAL exttype();
 
+/* xget_env - get the value of an environment variable */
+LVAL xget_env(void)
+{
+    const char *name = (char *) getstring(xlgetfname());
+    char *val;
+
+    /* check for too many arguments */
+    xllastarg();
+
+    /* get the value of the environment variable */
+    val = getenv(name);
+    return (val ? cvstring(val) : NULL);
+}
+
 /* xload - read and evaluate expressions from a file */
 LVAL xload(void)
 {