Stricter libc-client symlink check

Author: olemarkus

ext/imap/config.m4

@@ -198,9 +198,9 @@ if test "$PHP_IMAP" != "no"; then
       AC_MSG_ERROR(Cannot find rfc822.h. Please check your c-client installation.)
     fi
 
-    if test -r "$IMAP_DIR/c-client/c-client.a"; then
+    if test ! -r "$IMAP_DIR/c-client/libc-client.a" && -r "$IMAP_DIR/c-client/c-client.a" ; then
       ln -s "$IMAP_DIR/c-client/c-client.a" "$IMAP_DIR/c-client/libc-client.a" >/dev/null 2>&1
-    elif test -r "$IMAP_DIR/$PHP_LIBDIR/c-client.a"; then
+    elif test ! -r "$IMAP_DIR/$PHP_LIBDIR/libc-client.a" && -r "$IMAP_DIR/$PHP_LIBDIR/c-client.a"; then
       ln -s "$IMAP_DIR/$PHP_LIBDIR/c-client.a" "$IMAP_DIR/$PHP_LIBDIR/libc-client.a" >/dev/null 2>&1
     fi