fix compile warning on Solaris, getloadavg() is in sys/loadavg.h there

configure.in

@@ -372,6 +372,7 @@ sys/vfs.h \
 sys/sysexits.h \
 sys/varargs.h \
 sys/wait.h \
+sys/loadavg.h \
 termios.h \
 unistd.h \
 unix.h \

ext/standard/basic_functions.c

@@ -78,6 +78,10 @@ typedef struct yy_buffer_state *YY_BUFFER_STATE;
 # include <sys/mman.h>
 #endif
 
+#if HAVE_SYS_LOADAVG_H
+# include <sys/loadavg.h>
+#endif
+
 #ifdef HARTMUT_0
 #include <getopt.h>
 #endif