MT#55283 defuse ifunc for unsupported targets

Let's see if this fixes builds for ARM on Debian <11.

Change-Id: I826a4d98237d143ff0cd3561453fd7e129fdd719
(cherry picked from commit 915c408f68)

lib/codeclib.c

@@ -37,7 +37,7 @@ static packetizer_f packetizer_samplestream; // flat stream of samples
 static packetizer_f packetizer_amr;
 
 
-#ifndef ASAN_BUILD
+#if !defined(ASAN_BUILD) && HAS_ATTR(ifunc)
 static void (*resolve_float2int16_array(void))(float *, const uint16_t, int16_t *);
 static void float2int16_array(float *in, const uint16_t len, int16_t *out)
 	__attribute__ ((ifunc ("resolve_float2int16_array")));

lib/mix_buffer.c

@@ -53,7 +53,7 @@ static void s16_mix_in_c(void *restrict dst, const void *restrict src, unsigned
 }
 
 
-#ifndef ASAN_BUILD
+#if !defined(ASAN_BUILD) && HAS_ATTR(ifunc)
 static mix_in_fn_t *resolve_s16_mix_in(void) {
 #if defined(__x86_64__)
 	if (rtpe_has_cpu_flag(RTPE_CPU_FLAG_AVX512BW))