diff --git a/cpanspec.yml b/cpanspec.yml
index 24fab1f..1b5942a 100644
--- a/cpanspec.yml
+++ b/cpanspec.yml
@@ -10,6 +10,8 @@
 #patches:
 #  foo.patch: -p1
 #  bar.patch:
+format.patch: -p1
+undefined.patch: -p1
 #preamble: |-
 # BuildRequires:  gcc-c++
 #post_prep: |-
diff --git a/format.patch b/format.patch
new file mode 100644
index 0000000..e2fc065
--- /dev/null
+++ b/format.patch
@@ -0,0 +1,13 @@
+Index: List-MoreUtils-XS-0.423/XS.xs
+===================================================================
+--- List-MoreUtils-XS-0.423.orig/XS.xs
++++ List-MoreUtils-XS-0.423/XS.xs
+@@ -2310,7 +2310,7 @@ CODE:
+         idx = SvIV(*PL_stack_sp);
+ 
+         if (UNLIKELY(idx < 0 && (idx += (AvFILLp(tmp)+1)) < 0))
+-            croak("Modification of non-creatable array value attempted, subscript %ld", idx);
++            croak("Modification of non-creatable array value attempted, subscript %" IVdf, idx);
+ 
+         if(UNLIKELY(NULL == (inner = av_fetch(tmp, idx, FALSE))))
+         {
diff --git a/perl-List-MoreUtils-XS.changes b/perl-List-MoreUtils-XS.changes
index 86b3e85..a6a8063 100644
--- a/perl-List-MoreUtils-XS.changes
+++ b/perl-List-MoreUtils-XS.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Tue Sep 12 08:16:32 UTC 2017 - schwab@suse.de
+
+- format.patch: fix format errors
+- undefined.patch: fix undefined operation
+
 -------------------------------------------------------------------
 Mon Sep  4 05:39:47 UTC 2017 - coolo@suse.com
 
diff --git a/perl-List-MoreUtils-XS.spec b/perl-List-MoreUtils-XS.spec
index 10ab038..33237db 100644
--- a/perl-List-MoreUtils-XS.spec
+++ b/perl-List-MoreUtils-XS.spec
@@ -27,6 +27,8 @@ Group:          Development/Libraries/Perl
 Url:            http://search.cpan.org/dist/List-MoreUtils-XS/
 Source0:        https://cpan.metacpan.org/authors/id/R/RE/REHSACK/%{cpan_name}-%{version}.tar.gz
 Source1:        cpanspec.yml
+Patch0:         format.patch
+Patch1:         undefined.patch
 BuildRoot:      %{_tmppath}/%{name}-%{version}-build
 BuildRequires:  perl
 BuildRequires:  perl-macros
@@ -44,6 +46,8 @@ only a backend, the API is not public and can change without any warning.
 
 %prep
 %setup -q -n %{cpan_name}-%{version}
+%patch0 -p1
+%patch1 -p1
 
 %build
 %{__perl} Makefile.PL INSTALLDIRS=vendor OPTIMIZE="%{optflags}"
diff --git a/undefined.patch b/undefined.patch
new file mode 100644
index 0000000..7a21e47
--- /dev/null
+++ b/undefined.patch
@@ -0,0 +1,14 @@
+Index: List-MoreUtils-XS-0.423/XS.xs
+===================================================================
+--- List-MoreUtils-XS-0.423.orig/XS.xs
++++ List-MoreUtils-XS-0.423/XS.xs
+@@ -2114,7 +2114,8 @@ CODE:
+ 
+     if(seen_undef == max)
+     {
+-        EXTEND(SP, ++count);
++        ++count;
++        EXTEND(SP, count);
+         ST(count-1) = &PL_sv_undef;
+     }
+