KFreeBSD is also an ELF binary

Fixes: #5733

aclocal.m4

@@ -212,13 +212,16 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
         freebsd)
             test -z "[$]2" || eval "[$]2=OSFreeBSD"
             ;;
+        kfreebsdgnu)
+            test -z "[$]2" || eval "[$]2=OSKFreeBSD"
+            ;;
         openbsd)
             test -z "[$]2" || eval "[$]2=OSOpenBSD"
             ;;
         netbsd)
             test -z "[$]2" || eval "[$]2=OSNetBSD"
             ;;
-        dragonfly|osf1|osf3|hpux|linuxaout|kfreebsdgnu|freebsd2|cygwin32|gnu|nextstep2|nextstep3|sunos4|ultrix|irix|aix|haiku)
+        dragonfly|osf1|osf3|hpux|linuxaout|freebsd2|cygwin32|gnu|nextstep2|nextstep3|sunos4|ultrix|irix|aix|haiku)
             test -z "[$]2" || eval "[$]2=OSUnknown"
             ;;
         *)

compiler/utils/Platform.hs

@@ -56,6 +56,7 @@ data OS
         | OSFreeBSD
         | OSOpenBSD
         | OSNetBSD
+        | OSKFreeBSD
         deriving (Read, Show, Eq)
 
 -- | ARM Instruction Set Architecture and Extensions
@@ -87,6 +88,7 @@ osElfTarget OSNetBSD   = True
 osElfTarget OSSolaris2 = True
 osElfTarget OSDarwin   = False
 osElfTarget OSMinGW32  = False
+osElfTarget OSKFreeBSD = True
 osElfTarget OSUnknown  = False
  -- Defaulting to False is safe; it means don't rely on any
  -- ELF-specific functionality.  It is important to have a default for