diff --git a/flex-2.5.37-types.patch b/flex-2.5.37-types.patch
new file mode 100644
index 0000000..560a640
--- /dev/null
+++ b/flex-2.5.37-types.patch
@@ -0,0 +1,41 @@
+From c53fd2db8c78fef5afd284c3e64da51bc71cf6c3 Mon Sep 17 00:00:00 2001
+From: nomis52 <nomis52@users.sourceforge.net>
+Date: Sat, 4 Aug 2012 15:03:31 -0400
+Subject: [PATCH] Change variable types to silence compiler warnings; resolves
+ #3552806
+
+Signed-off-by: Will Estes <westes575@gmail.com>
+---
+ flex.skl |    2 +-
+ gen.c    |    2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/flex.skl b/flex.skl
+index 01d8204..7802f45 100644
+--- a/flex.skl
++++ b/flex.skl
+@@ -2360,7 +2360,7 @@ YY_BUFFER_STATE yy_scan_bytes  YYFARGS2( yyconst char *,yybytes, yy_size_t ,_yyb
+ 	YY_BUFFER_STATE b;
+ 	char *buf;
+ 	yy_size_t n;
+-	int i;
++	yy_size_t i;
+     m4_dnl M4_YY_DECL_GUTS_VAR();
+ 
+ 	/* Get memory for full buffer, including space for trailing EOB's. */
+diff --git a/gen.c b/gen.c
+index 5a5daef..8d24a86 100644
+--- a/gen.c
++++ b/gen.c
+@@ -1972,7 +1972,7 @@ void make_tables ()
+ 		("if ( yy_act != YY_END_OF_BUFFER && yy_rule_can_match_eol[yy_act] )");
+ 	indent_up ();
+ 	indent_puts ("{");
+-	indent_puts ("int yyl;");
++	indent_puts ("yy_size_t yyl;");
+ 	do_indent ();
+ 	out_str ("for ( yyl = %s; yyl < yyleng; ++yyl )\n",
+ 		 yymore_used ? (yytext_is_array ? "YY_G(yy_prev_more_offset)" :
+-- 
+1.7.6.5
+
diff --git a/flex.spec b/flex.spec
index c22a8a6..2571020 100644
--- a/flex.spec
+++ b/flex.spec
@@ -1,7 +1,7 @@
 Summary: A tool for creating scanners (text pattern recognizers)
 Name: flex
 Version: 2.5.37
-Release: 3%{?dist}
+Release: 4%{?dist}
 # parse.c and parse.h are under GPLv3+ with exception which allows
 #	relicensing.  Since flex is shipped under BDS-style license,
 #	let's  assume that the relicensing was done.
@@ -17,6 +17,9 @@ Patch0: flex-2.5.36-bison-2.6.1.patch
 # https://bugzilla.redhat.com/show_bug.cgi?id=925801
 Patch1: flex-2.5.37-aarch64.patch
 
+# https://bugzilla.redhat.com/show_bug.cgi?id=993447
+Patch2: flex-2.5.37-types.patch
+
 BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 Requires: m4
 BuildRequires: gettext bison m4
@@ -64,6 +67,7 @@ plain text and PDF formats.
 %setup -q
 %patch0 -p1
 %patch1 -p1
+%patch2 -p1
 
 %global flexdocdir %{_datadir}/doc/flex-doc-%{version}
 
@@ -124,6 +128,11 @@ rm -rf ${RPM_BUILD_ROOT}
 %{_datadir}/doc/flex-doc-%{version}
 
 %changelog
+* Tue Sep  3 2013 Petr Machata <pmachata@redhat.com> - 2.5.37-4
+- Add a patch for "comparison between signed and unsigned" warnings
+  that GCC produces when compiling flex-generated scanners
+  (flex-2.5.37-types.patch)
+
 * Sat Aug 03 2013 Fedora Release Engineering <rel-eng@lists.fedoraproject.org> - 2.5.37-3
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_20_Mass_Rebuild