Proper warning silencing patch for Clang

[Dmitry Golovin <dima@golovin.in>]

[-- Attachment #1: Type: text/plain, Size: 350 bytes --]

Hi!

This time the patch doesn't break anything. Check for supported optimizations is performed using "-Werror=ignored-optimization-argument" (clang specific) and also "-Qunused-arguments" is added to silence unused argument warnings (ignoring unused arguments is default behavior for GCC, but not for Clang).

The patch is attached.

Regards,
Dmitry

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-add-proper-check-for-clang-supported-optimization-an.patch --]
[-- Type: text/x-diff; name="0001-add-proper-check-for-clang-supported-optimization-an.patch", Size: 1245 bytes --]

From c37efc541b12d8e216b7a425808e4c24c48f9213 Mon Sep 17 00:00:00 2001
From: Dmitry Golovin <dima@golovin.in>
Date: Fri, 9 Jun 2017 16:41:53 +0300
Subject: [PATCH] add proper check for clang supported optimization and stop
 complaining about unused arguements

---
 configure | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/configure b/configure
index c2db298..539c9fc 100755
--- a/configure
+++ b/configure
@@ -249,6 +249,7 @@ fi
 #
 tryflag   CFLAGS_TRY  -Werror=unknown-warning-option
 tryflag   CFLAGS_TRY  -Werror=unused-command-line-argument
+tryflag   CFLAGS_TRY  -Werror=ignored-optimization-argument
 tryldflag LDFLAGS_TRY -Werror=unknown-warning-option
 tryldflag LDFLAGS_TRY -Werror=unused-command-line-argument
 
@@ -504,6 +505,13 @@ tryflag CFLAGS_AUTO -Werror=implicit-int
 tryflag CFLAGS_AUTO -Werror=pointer-sign
 tryflag CFLAGS_AUTO -Werror=pointer-arith
 
+#
+# GCC ignores unused arguements by default, but Clang needs this extra
+# parameter to stop printing warnings about LDFLAGS passed during
+# compiling stage and CFLAGS passed during linking stage.
+#
+tryflag CFLAGS_AUTO -Qunused-arguments
+
 if test "x$warnings" = xyes ; then
 tryflag CFLAGS_AUTO -Wall
 tryflag CFLAGS_AUTO -Wno-parentheses
-- 
2.13.0