[compiler-rt] Disable tests for unavailable builtins (#158664)

The builtins `__fixunstfdi` and `__multc3` may be removed by the
preprocessor depending on configuration flags. When this happens, the
corresponding tests fail at link time due to missing definitions.

Disable these tests when the builtins are not available.

rdar://159705803
rdar://159705705

Author: ahatanak

compiler-rt/test/builtins/Unit/fixunstfdi_test.c

@@ -4,7 +4,7 @@
 
 #include <stdio.h>
 
-#if _ARCH_PPC || __aarch64__ || __arm64ec__
+#if defined(CRT_HAS_TF_MODE)
 
 #include "int_lib.h"
 
@@ -35,7 +35,7 @@ char assumption_3[sizeof(long double)*CHAR_BIT == 128] = {0};
 
 int main()
 {
-#if _ARCH_PPC || __aarch64__ || __arm64ec__
+#if defined(CRT_HAS_TF_MODE)
     if (test__fixunstfdi(0.0, 0))
         return 1;
 

compiler-rt/test/builtins/Unit/multc3_test.c

@@ -4,7 +4,7 @@
 
 #include <stdio.h>
 
-#if _ARCH_PPC || __aarch64__ || __arm64ec__
+#if defined(CRT_HAS_128BIT) && defined(CRT_HAS_F128)
 
 #include "int_lib.h"
 #include <math.h>
@@ -348,7 +348,7 @@ long double x[][2] =
 
 int main()
 {
-#if _ARCH_PPC || __aarch64__ || __arm64ec__
+#if defined(CRT_HAS_128BIT) && defined(CRT_HAS_F128)
     const unsigned N = sizeof(x) / sizeof(x[0]);
     unsigned i, j;
     for (i = 0; i < N; ++i)