intfloat: Don't use designated initializers in the public headers

intfloat.h is a public header, and is now (since a1245d5c) included
by mathematics.h, which many external callers include.

This fixes building third party applications that include
mathematics.h in a language that doesn't support designated
initalizers.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavutil/intfloat.h

@@ -39,7 +39,8 @@ union av_intfloat64 {
  */
 static av_always_inline float av_int2float(uint32_t i)
 {
-    union av_intfloat32 v = { .i = i };
+    union av_intfloat32 v;
+    v.i = i;
     return v.f;
 }
 
@@ -48,7 +49,8 @@ static av_always_inline float av_int2float(uint32_t i)
  */
 static av_always_inline uint32_t av_float2int(float f)
 {
-    union av_intfloat32 v = { .f = f };
+    union av_intfloat32 v;
+    v.f = f;
     return v.i;
 }
 
@@ -57,7 +59,8 @@ static av_always_inline uint32_t av_float2int(float f)
  */
 static av_always_inline double av_int2double(uint64_t i)
 {
-    union av_intfloat64 v = { .i = i };
+    union av_intfloat64 v;
+    v.i = i;
     return v.f;
 }
 
@@ -66,7 +69,8 @@ static av_always_inline double av_int2double(uint64_t i)
  */
 static av_always_inline uint64_t av_double2int(double f)
 {
-    union av_intfloat64 v = { .f = f };
+    union av_intfloat64 v;
+    v.f = f;
     return v.i;
 }