[NetworkManager-pptp/lr/ci: 4/5] build: find is required by libtool

[Francesco Giudici <fgiudici src gnome org>]

commit de1de86856c0a37ff9e6d7a8d165b93640b57a78
Author: Lubomir Rintel <lkundrak v3 sk>
Date:   Tue May 29 10:34:21 2018 +0200

    build: find is required by libtool
    
    It's not necessarily present among the packages in a minimal
    installation (such as Fedora's docker image). Worse even, libtool just
    ends up not linking to some .la libraries.
    
    Don't assume it's there.

 configure.ac | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/configure.ac b/configure.ac
index 7c7cd89..f5d205f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,6 +26,11 @@ if test x$has_file = xno ; then
     AC_MSG_ERROR(["file" utility not found.])
 fi
 
+AC_CHECK_PROG([has_find], find, yes, no)
+if test x$has_find = xno ; then
+    AC_MSG_ERROR(["find" utility not found.])
+fi
+
 dnl
 dnl Required headers
 dnl