Merge branch 'wip/ppc-lynx178' into 'master'

ppc-lynx178: move to ada math functions and disable FPU

See merge request eng/toolchain/bb-runtimes!147

lynx/__init__.py

@@ -10,14 +10,6 @@ def __init__(self):
     def has_libc(self, profile):
         return True
 
-    @property
-    def has_single_precision_fpu(self):
-        return True
-
-    @property
-    def has_double_precision_fpu(self):
-        return True
-
     @property
     def is_os_target(self):
         return True
@@ -35,6 +27,12 @@ class PPCLynx(Lynx):
     def __init__(self):
         super().__init__()
 
+    @property
+    def has_double_precision_fpu(self):
+        # Disable FPU support. Otherwise, `__builtins_*` could fallbacks
+        # on missing features of LynxOS libm.
+        return False
+
     @property
     def target(self):
         return "ppc-lynx178"