From 94b2632a1f05af8d0bc6fdd14c0cde011efc0860 Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <moritz@bunkus.org>
Date: Mon, 1 Apr 2013 20:40:30 +0200
Subject: [PATCH] build system: avoid certain warnings with Qt and clang

---
 Rakefile        |  1 +
 ac/clang.m4     | 30 +++++++++++++++++++++++++++++-
 build-config.in |  2 ++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/Rakefile b/Rakefile
index a6022b7af..45bb0ea72 100644
--- a/Rakefile
+++ b/Rakefile
@@ -89,6 +89,7 @@ def setup_globals
   $build_tools           ||=  c?(:TOOLS)
 
   cflags_common            = "-Wall -Wno-comment -Wfatal-errors "
+  cflags_common           += "#{c(:WNO_SELF_ASSIGN)} " if c?(:USE_CLANG) && c?(:USE_QT)
   cflags_common           += "#{c(:OPTIMIZATION_CFLAGS)} -D_FILE_OFFSET_BITS=64 #{c(:MATROSKA_CFLAGS)} #{c(:EBML_CFLAGS)} #{c(:EXTRA_CFLAGS)} #{c(:DEBUG_CFLAGS)} #{c(:PROFILING_CFLAGS)} #{c(:USER_CPPFLAGS)} "
   cflags_common           += "-DPACKAGE=\\\"#{c(:PACKAGE)}\\\" -DVERSION=\\\"#{c(:VERSION)}\\\" -DMTX_LOCALE_DIR=\\\"#{c(:localedir)}\\\" -DMTX_PKG_DATA_DIR=\\\"#{c(:pkgdatadir)}\\\" -DMTX_DOC_DIR=\\\"#{c(:docdir)}\\\" "
   cflags_common           += "#{c(:QUNUSED_ARGUMENTS)}"
diff --git a/ac/clang.m4 b/ac/clang.m4
index 1ef6b0cbb..99b52622d 100644
--- a/ac/clang.m4
+++ b/ac/clang.m4
@@ -1,7 +1,8 @@
 AC_DEFUN([AX_COMPILER_IS_CLANG],[
   AC_CACHE_CHECK([compiler is clang], [ac_cv_compiler_is_clang], [
-    if $CXX --version | grep -q -i 'clang.*llvm' ; then
+    if $CXX --version | grep -q -i clang ; then
       ac_cv_compiler_is_clang=yes
+      USE_CLANG=yes
     else
       ac_cv_compiler_is_clang=no
     fi
@@ -33,5 +34,32 @@ AC_DEFUN([AX_QUNUSED_ARGUMENTS_FLAG],[
   AC_SUBST(QUNUSED_ARGUMENTS)
 ])
 
+AC_DEFUN([AX_WNO_SELF_ASSIGN_FLAG],[
+  AC_CACHE_CHECK([for the compiler flag "-Wno-self-assign"], [ax_cv_wno_self_assign_flag],[
+
+    CXXFLAGS_SAVED=$CXXFLAGS
+    CXXFLAGS="$CXXFLAGS -Wno-self-assign"
+    export CXXFLAGS
+
+    AC_LANG_PUSH(C++)
+    AC_TRY_COMPILE(
+      [],
+      [1;],
+      [ax_cv_wno_self_assign_flag="yes"],
+      [ax_cv_wno_self_assign_flag="no"])
+    AC_LANG_POP
+
+    CXXFLAGS="$CXXFLAGS_SAVED"
+  ])
+
+  WNO_SELF_ASSIGN=""
+  if test x"$ax_cv_wno_self_assign_flag" = xyes ; then
+    WNO_SELF_ASSIGN="-Wno-self-assign"
+  fi
+  AC_SUBST(WNO_SELF_ASSIGN)
+])
+
 AX_QUNUSED_ARGUMENTS_FLAG
+AX_WNO_SELF_ASSIGN_FLAG
 AX_COMPILER_IS_CLANG
+AC_SUBST(USE_CLANG)
diff --git a/build-config.in b/build-config.in
index b5896bd79..3d118a68c 100644
--- a/build-config.in
+++ b/build-config.in
@@ -104,12 +104,14 @@ QT_CFLAGS = @QT_CFLAGS@
 QT_LIBS = @QT_LIBS@
 QUNUSED_ARGUMENTS = @QUNUSED_ARGUMENTS@
 STD_CXX0X = @STD_CXX0X@
+USE_CLANG = @USE_CLANG@
 USE_PRECOMPILED_HEADERS = @USE_PRECOMPILED_HEADERS@
 USER_CPPFLAGS = @USER_CPPFLAGS@
 USER_CXXFLAGS = @USER_CXXFLAGS@
 USER_CFLAGS = @USER_CFLAGS@
 USER_LDFLAGS = @USER_LDFLAGS@
 VORBIS_LIBS = @VORBIS_LIBS@
+WNO_SELF_ASSIGN = @WNO_SELF_ASSIGN@
 WXWIDGETS_CFLAGS = @WXWIDGETS_CFLAGS@
 WXWIDGETS_INCLUDES = @WXWIDGETS_INCLUDES@
 WXWIDGETS_LIBS = @WXWIDGETS_LIBS@