https://bugs.gentoo.org/545114

extracted from the upstream change (which had many unrelated commits in one)

From 97bb4678dc03e753290b39bbff30ba2825df9517 Mon Sep 17 00:00:00 2001
From: "Thomas E. Dickey" <dickey@invisible-island.net>
Date: Sun, 7 Dec 2014 03:10:09 +0000
Subject: [PATCH] ncurses 5.9 - patch 20141206

+ modify MKlib_gen.sh to work around change in development version of
  gcc introduced here:
	  https://gcc.gnu.org/ml/gcc-patches/2014-06/msg02185.html
	  https://gcc.gnu.org/ml/gcc-patches/2014-07/msg00236.html
  (reports by Marcus Shawcroft, Maohui Lei).

--- a/ncurses/base/MKlib_gen.sh
+++ b/ncurses/base/MKlib_gen.sh
@@ -491,11 +491,22 @@ sed -n -f $ED1 \
 	-e 's/gen_$//' \
 	-e 's/  / /g' >>$TMP
 
+cat >$ED1 <<EOF
+s/  / /g
+s/^ //
+s/ $//
+s/P_NCURSES_BOOL/NCURSES_BOOL/g
+EOF
+
+# A patch discussed here:
+#	https://gcc.gnu.org/ml/gcc-patches/2014-06/msg02185.html
+# introduces spurious #line markers.  Work around that by ignoring the system's
+# attempt to define "bool" and using our own symbol here.
+sed -e 's/bool/P_NCURSES_BOOL/g' $TMP > $ED2
+cat $ED2 >$TMP
+
 $preprocessor $TMP 2>/dev/null \
-| sed \
-	-e 's/  / /g' \
-	-e 's/^ //' \
-	-e 's/_Bool/NCURSES_BOOL/g' \
+| sed -f $ED1 \
 | $AWK -f $AW2 \
 | sed -f $ED3 \
 | sed \
