Patch for faad_imdct in FAAD2 for GCC 9

mdct.patch

diff --git a/libfaad/mdct.c b/libfaad/mdct.c
index 247691e..1545357 100644
--- a/libfaad/mdct.c
+++ b/libfaad/mdct.c
@@ -121,21 +121,18 @@ void faad_mdct_end(mdct_info *mdct)
 
 void faad_imdct(mdct_info *mdct, real_t *X_in, real_t *X_out)
 {
-    uint16_t k;
-
-    complex_t x;
 #ifdef ALLOW_SMALL_FRAMELENGTH
 #ifdef FIXED_POINT
     real_t scale, b_scale = 0;
 #endif
 #endif
     ALIGN complex_t Z1[512];
-    complex_t *sincos = mdct->sincos;
+    const complex_t *sincos = mdct->sincos;
 
-    uint16_t N  = mdct->N;
-    uint16_t N2 = N >> 1;
-    uint16_t N4 = N >> 2;
-    uint16_t N8 = N >> 3;
+    const unsigned int N  = mdct->N;
+    const unsigned int N2 = N >> 1;
+    const unsigned int N4 = N >> 2;
+    const unsigned int N8 = N >> 3;
 
 #ifdef PROFILE
     int64_t count1, count2 = faad_get_ts();
@@ -155,7 +152,7 @@ void faad_imdct(mdct_info *mdct, real_t *X_in, real_t *X_out)
 #endif
 
     /* pre-IFFT complex multiplication */
-    for (k = 0; k < N4; k++)
+    for (unsigned int k = 0; k < N4; k++)
     {
         ComplexMult(&IM(Z1[k]), &RE(Z1[k]),
             X_in[2*k], X_in[N2 - 1 - 2*k], RE(sincos[k]), IM(sincos[k]));
@@ -173,12 +170,10 @@ void faad_imdct(mdct_info *mdct, real_t *X_in, real_t *X_out)
 #endif
 
     /* post-IFFT complex multiplication */
-    for (k = 0; k < N4; k++)
+    for (unsigned int k = 0; k < N4; k++)
     {
-        RE(x) = RE(Z1[k]);
-        IM(x) = IM(Z1[k]);
         ComplexMult(&IM(Z1[k]), &RE(Z1[k]),
-            IM(x), RE(x), RE(sincos[k]), IM(sincos[k]));
+            IM(Z1[k]), RE(Z1[k]), RE(sincos[k]), IM(sincos[k]));
 
 #ifdef ALLOW_SMALL_FRAMELENGTH
 #ifdef FIXED_POINT
@@ -193,7 +188,7 @@ void faad_imdct(mdct_info *mdct, real_t *X_in, real_t *X_out)
     }
 
     /* reordering */
-    for (k = 0; k < N8; k+=2)
+    for (unsigned int k = 0; k < N8; k+=2)
     {
         X_out[              2*k] =  IM(Z1[N8 +     k]);
         X_out[          2 + 2*k] =  IM(Z1[N8 + 1 + k]);