diff --git a/flex-2.5.33-yy.patch b/flex-2.5.33-yy.patch
new file mode 100644
index 0000000..e229c0e
--- /dev/null
+++ b/flex-2.5.33-yy.patch
@@ -0,0 +1,72 @@
+diff -urp flex-2.5.33/flex.skl flex-2.5.33-pm/flex.skl
+--- flex-2.5.33/flex.skl	2006-02-16 23:20:43.000000000 +0100
++++ flex-2.5.33-pm/flex.skl	2007-03-30 14:04:42.000000000 +0200
+@@ -54,6 +54,32 @@ m4_changequote([[, ]])
+ %#   the generated scanner as a C-style comment. This is to aid those who
+ %#   edit the skeleton.
+ %#
++
++%not-for-header
++%if-not-reentrant
++m4_ifelse(M4_YY_PREFIX,yy,,
++#define yy_create_buffer M4_YY_PREFIX[[_create_buffer]]
++#define yy_delete_buffer M4_YY_PREFIX[[_delete_buffer]]
++#define yy_flex_debug M4_YY_PREFIX[[_flex_debug]]
++#define yy_init_buffer M4_YY_PREFIX[[_init_buffer]]
++#define yy_flush_buffer M4_YY_PREFIX[[_flush_buffer]]
++#define yy_load_buffer_state M4_YY_PREFIX[[_load_buffer_state]]
++#define yy_switch_to_buffer M4_YY_PREFIX[[_switch_to_buffer]]
++#define yyin M4_YY_PREFIX[[in]]
++#define yyleng M4_YY_PREFIX[[leng]]
++#define yylex M4_YY_PREFIX[[lex]]
++#define yylineno M4_YY_PREFIX[[lineno]]
++#define yyout M4_YY_PREFIX[[out]]
++#define yyrestart M4_YY_PREFIX[[restart]]
++#define yytext M4_YY_PREFIX[[text]]
++#define yywrap M4_YY_PREFIX[[wrap]]
++#define yyalloc M4_YY_PREFIX[[alloc]]
++#define yyrealloc M4_YY_PREFIX[[realloc]]
++#define yyfree M4_YY_PREFIX[[free]]
++)
++%endif
++%ok-for-header
++
+ #define FLEX_SCANNER
+ #define YY_FLEX_MAJOR_VERSION FLEX_MAJOR_VERSION
+ #define YY_FLEX_MINOR_VERSION FLEX_MINOR_VERSION
+diff -urp flex-2.5.33/skel.c flex-2.5.33-pm/skel.c
+--- flex-2.5.33/skel.c	2006-02-21 03:45:41.000000000 +0100
++++ flex-2.5.33-pm/skel.c	2007-03-30 14:04:43.000000000 +0200
+@@ -59,6 +59,32 @@ const char *skel[] = {
+   "%#   the generated scanner as a C-style comment. This is to aid those who",
+   "%#   edit the skeleton.",
+   "%#",
++  "",
++  "%not-for-header",
++  "%if-not-reentrant",
++  "m4_ifelse(M4_YY_PREFIX,yy,,",
++  "#define yy_create_buffer M4_YY_PREFIX[[_create_buffer]]",
++  "#define yy_delete_buffer M4_YY_PREFIX[[_delete_buffer]]",
++  "#define yy_flex_debug M4_YY_PREFIX[[_flex_debug]]",
++  "#define yy_init_buffer M4_YY_PREFIX[[_init_buffer]]",
++  "#define yy_flush_buffer M4_YY_PREFIX[[_flush_buffer]]",
++  "#define yy_load_buffer_state M4_YY_PREFIX[[_load_buffer_state]]",
++  "#define yy_switch_to_buffer M4_YY_PREFIX[[_switch_to_buffer]]",
++  "#define yyin M4_YY_PREFIX[[in]]",
++  "#define yyleng M4_YY_PREFIX[[leng]]",
++  "#define yylex M4_YY_PREFIX[[lex]]",
++  "#define yylineno M4_YY_PREFIX[[lineno]]",
++  "#define yyout M4_YY_PREFIX[[out]]",
++  "#define yyrestart M4_YY_PREFIX[[restart]]",
++  "#define yytext M4_YY_PREFIX[[text]]",
++  "#define yywrap M4_YY_PREFIX[[wrap]]",
++  "#define yyalloc M4_YY_PREFIX[[alloc]]",
++  "#define yyrealloc M4_YY_PREFIX[[realloc]]",
++  "#define yyfree M4_YY_PREFIX[[free]]",
++  ")",
++  "%endif",
++  "%ok-for-header",
++  "",
+   "#define FLEX_SCANNER",
+   "#define YY_FLEX_MAJOR_VERSION 2",
+   "#define YY_FLEX_MINOR_VERSION 5",
diff --git a/flex.spec b/flex.spec
index 74fb94b..a908987 100644
--- a/flex.spec
+++ b/flex.spec
@@ -1,12 +1,13 @@
 Summary: A tool for creating scanners (text pattern recognizers)
 Name: flex
 Version: 2.5.33
-Release: 4%{?dist}
+Release: 5%{?dist}
 License: BSD
 Group: Development/Tools
 URL: http://flex.sourceforge.net/
-Source: http://puzzle.dl.sourceforge.net/sourceforge/flex/flex-%{version}.tar.bz2
+Source: flex-%{version}.tar.bz2
 Patch0: flex-2.5.33-pic.patch
+Patch1: flex-2.5.33-yy.patch
 BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 Requires: m4
 BuildRequires: gettext info bison m4
@@ -30,6 +31,7 @@ application development.
 %prep
 %setup -q
 %patch0 -p1
+%patch1 -p1
 
 %build
 %configure --disable-dependency-tracking
@@ -60,7 +62,7 @@ fi
 
 %check
 echo ============TESTING===============
-#make check
+make check
 echo ============END TESTING===========
 
 %clean
@@ -76,6 +78,9 @@ rm -rf ${RPM_BUILD_ROOT}
 %{_infodir}/flex.info*
 
 %changelog
+* Fri Mar 30 2007 Petr Machata <pmachata@redhat.com> - 2.5.33-5
+- Make yy-prefixed variables available to scanner even with -P.
+
 * Fri Feb  2 2007 Petr Machata <pmachata@redhat.com> - 2.5.33-4
 - Use %%find_lang to package locale files.