made Curl_nss_send() take const data to kill compiler warning

lib/Makefile.am

@@ -47,8 +47,8 @@ LIBCURL_LIBS = @LIBCURL_LIBS@
 # we use srcdir/lib for the lib-private header files
 
 INCLUDES = -I$(top_srcdir)/include \
-           -I$(top_builddir)/lib   \
-           -I$(top_srcdir)/lib
+           -I$(top_builddir)/lib
+
 
 VERSION=-version-info 5:0:1
 

lib/nss.c

@@ -1195,7 +1195,7 @@ error:
 /* return number of sent (non-SSL) bytes */
 int Curl_nss_send(struct connectdata *conn,  /* connection data */
                   int sockindex,             /* socketindex */
-                  void *mem,                 /* send this data */
+                  const void *mem,           /* send this data */
                   size_t len)                /* amount to write */
 {
   PRInt32 err;

lib/nssg.h

@@ -45,7 +45,7 @@ void Curl_nss_cleanup(void);
 
 int Curl_nss_send(struct connectdata *conn,
                   int sockindex,
-                  void *mem,
+                  const void *mem,
                   size_t len);
 ssize_t Curl_nss_recv(struct connectdata *conn, /* connection data */
                       int num,                  /* socketindex */