diff --git a/gccwarns.diff b/gccwarns.diff
new file mode 100644
index 0000000..3d35c98
--- /dev/null
+++ b/gccwarns.diff
@@ -0,0 +1,35 @@
+
+[  191s] searchinpath.c: In function 'searchonefile':
+[  191s] searchinpath.c:221:5: warning: implicit declaration of function 'eaccess'; did you mean 'access'? [-Wimplicit-function-declaration]
+[  191s]     (eaccess(nbuf, mode) >= 0)) {
+[  836s] create.c: In function 'flush_link':
+[  836s] create.c:1099:16: warning: 'finfo.f_flags' is used uninitialized in this function [-Wuninitialized]
+[  836s]   finfo.f_flags &= ~F_TCB_BUF;
+
+---
+ libschily/searchinpath.c |    1 +
+ star/create.c            |    2 +-
+ 2 files changed, 2 insertions(+), 1 deletion(-)
+
+Index: schily-2018-03-16/libschily/searchinpath.c
+===================================================================
+--- schily-2018-03-16.orig/libschily/searchinpath.c
++++ schily-2018-03-16/libschily/searchinpath.c
+@@ -1,3 +1,4 @@
++#define _GNU_SOURCE 1 /* eaccess */
+ /* @(#)searchinpath.c	1.6 18/02/04 Copyright 1999-2018 J. Schilling */
+ #include <schily/mconfig.h>
+ #ifndef lint
+Index: schily-2018-03-16/star/create.c
+===================================================================
+--- schily-2018-03-16.orig/star/create.c
++++ schily-2018-03-16/star/create.c
+@@ -1090,7 +1090,7 @@ flush_link(lp)
+ {
+ 		TCB	tb;
+ 		TCB	*ptb;
+-		FINFO	finfo;
++		FINFO	finfo = {};
+ 	register LNAME	*ln;
+ 		int	fd = 1;
+ 		BOOL	did_stat;
diff --git a/schily.changes b/schily.changes
index 052d966..6ea619d 100644
--- a/schily.changes
+++ b/schily.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Wed May 16 13:50:57 UTC 2018 - jengelh@inai.de
+
+- Add gccwarns.diff to address some undefined behavior.
+
 -------------------------------------------------------------------
 Mon May 14 09:28:34 UTC 2018 - jengelh@inai.de
 
diff --git a/schily.spec b/schily.spec
index 0dc7a1e..496ed8c 100644
--- a/schily.spec
+++ b/schily.spec
@@ -33,6 +33,7 @@ Source:         https://downloads.sf.net/schilytools/%name-%rver.tar.bz2
 Patch1:         gcc48wa.diff
 Patch2:         mkisofs-j-crash.diff
 Patch3:         iconv-name.diff
+Patch4:         gccwarns.diff
 # Honor https://en.opensuse.org/openSUSE:Packaging_Patches_guidelines#Upstream_policy
 # and submit patches upstream FIRST (cc to the bspkg maintainer perhaps).
 BuildRoot:      %{_tmppath}/%{name}-%{version}-build
@@ -396,7 +397,7 @@ Features:
 
 %prep
 %setup -qn %name-%rver
-%patch -P 1 -P 2 -P 3 -p1
+%patch -P 1 -P 2 -P 3 -P 4 -p1
 find . "(" -type d -o -type f ")" -exec chmod u+w "{}" "+"
 
 %build