[SCM] libav/experimental: build: Support building using clang-usan and disable-optimization

[siretart at users.alioth.debian.org]

The following commit has been merged in the experimental branch:
commit 4d25c2bc76f0a708c2ba470b6bfeb547efe37115
Author: Katerina Barone-Adesi <katerinab at gmail.com>
Date:   Fri May 16 18:07:34 2014 +0200

    build: Support building using clang-usan and disable-optimization
    
    Clang Undefined Behaviour Sanitizer seems to make non-constant constant
    expressions, making the compilation fail when they are used within
    inline assembly if no optimization is requested.
    
    Add -O1 to the cflags to hide the misbehaviour.
    
    Bug-Id: 683

diff --git a/configure b/configure
index 6f84dfa..74a4df1 100755
--- a/configure
+++ b/configure
@@ -2443,7 +2443,7 @@ case "$toolchain" in
     ;;
     clang-usan)
         cc_default="clang"
-        add_cflags  -fsanitize=undefined
+        add_cflags  -fsanitize=undefined -O1
         add_ldflags -fsanitize=undefined
     ;;
     gcc-asan)

-- 
Libav/FFmpeg packaging