lavu/internal: rename macro E(x) to EXPAND(x)

Fixes bunch of warnings of E redefinition under clang.
Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavutil/internal.h

@@ -60,7 +60,7 @@
 
 // Some broken preprocessors need a second expansion
 // to be forced to tokenize __VA_ARGS__
-#define E(x) x
+#define EXPAND(x) x
 
 #define LOCAL_ALIGNED_A(a, t, v, s, o, ...)             \
     uint8_t la_##v[sizeof(t s o) + (a)];                \
@@ -70,16 +70,16 @@
     DECLARE_ALIGNED(a, t, la_##v) s o;                  \
     t (*v) o = la_##v
 
-#define LOCAL_ALIGNED(a, t, v, ...) E(LOCAL_ALIGNED_A(a, t, v, __VA_ARGS__,,))
+#define LOCAL_ALIGNED(a, t, v, ...) EXPAND(LOCAL_ALIGNED_A(a, t, v, __VA_ARGS__,,))
 
 #if HAVE_LOCAL_ALIGNED_8
-#   define LOCAL_ALIGNED_8(t, v, ...) E(LOCAL_ALIGNED_D(8, t, v, __VA_ARGS__,,))
+#   define LOCAL_ALIGNED_8(t, v, ...) EXPAND(LOCAL_ALIGNED_D(8, t, v, __VA_ARGS__,,))
 #else
 #   define LOCAL_ALIGNED_8(t, v, ...) LOCAL_ALIGNED(8, t, v, __VA_ARGS__)
 #endif
 
 #if HAVE_LOCAL_ALIGNED_16
-#   define LOCAL_ALIGNED_16(t, v, ...) E(LOCAL_ALIGNED_D(16, t, v, __VA_ARGS__,,))
+#   define LOCAL_ALIGNED_16(t, v, ...) EXPAND(LOCAL_ALIGNED_D(16, t, v, __VA_ARGS__,,))
 #else
 #   define LOCAL_ALIGNED_16(t, v, ...) LOCAL_ALIGNED(16, t, v, __VA_ARGS__)
 #endif