From 7276ab934d192627c72720ae1378de93edd9e8c7 Mon Sep 17 00:00:00 2001
From: Jay Berkenbilt <ejb@ql.org>
Date: Sun, 24 Feb 2013 15:29:17 -0500
Subject: Use -Wold-style-cast for C++ if supported

Also separate C and C++ warning flags.
---
 configure.ac | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

(limited to 'configure.ac')

diff --git a/configure.ac b/configure.ac
index 8b4c444b..d8f3b6ba 100644
--- a/configure.ac
+++ b/configure.ac
@@ -176,6 +176,7 @@ AC_ARG_WITH(buildrules,
 AC_MSG_RESULT($BUILDRULES)
 
 AC_SUBST(WFLAGS)
+AC_SUBST(CXXWFLAGS)
 qpdf_USE_EXTRA_WARNINGS=0
 if test "$BUILDRULES" = "msvc"; then
    dnl /w14267 makes warning 4267 a level 1 warning.  This warning reports
@@ -197,6 +198,22 @@ if test "$qpdf_USE_EXTRA_WARNINGS" = "1"; then
 else
    AC_MSG_RESULT(no)
 fi
+if test "$BUILDRULES" != "msvc"; then
+   qpdf_USE_EXTRA_WARNINGS=0
+   try_flags="-Wold-style-cast"
+   AC_MSG_CHECKING(for whether $CXX supports $try_flags)
+   oCXXFLAGS=$CXXFLAGS
+   CXXFLAGS="$CXXFLAGS $try_flags"
+   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[int a = 1; int b = a; a = b;]])],
+                     [qpdf_USE_EXTRA_WARNINGS=1],[qpdf_USE_EXTRA_WARNINGS=0])
+   CXXFLAGS=$oCXXFLAGS
+   if test "$qpdf_USE_EXTRA_WARNINGS" = "1"; then
+      AC_MSG_RESULT(yes)
+      CXXWFLAGS="$try_flags"
+   else
+      AC_MSG_RESULT(no)
+   fi
+fi
 
 if test "$BUILDRULES" = "msvc"; then
    try_flags="/WX"
-- 
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