[RFC PATCH 2/2] linux-user/mmap: Fix Clang 'type-limit-compare' warning

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

When building with Clang 10 on Fedora 32, we get:

    CC      linux-user/mmap.o
  linux-user/mmap.c:720:49: error: result of comparison 'unsigned long' > 18446744073709551615 is always false [-Werror,-Wtautological-type-limit-compare]
          if ((unsigned long)host_addr + new_size > (abi_ulong)-1) {
              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~

Fix by restricting the check for when target sizeof(abi_ulong) is
smaller than target sizeof(unsigned long).

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 linux-user/mmap.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index e378033797..b14652d894 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -714,6 +714,7 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
             errno = ENOMEM;
             host_addr = MAP_FAILED;
         }
+#if TARGET_ABI_BITS < TARGET_LONG_BITS
         /* Check if address fits target address space */
         if ((unsigned long)host_addr + new_size > (abi_ulong)-1) {
             /* Revert mremap() changes */
@@ -721,6 +722,7 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
             errno = ENOMEM;
             host_addr = MAP_FAILED;
         }
+#endif /* TARGET_ABI_BITS < TARGET_LONG_BITS */
     }
 
     if (host_addr == MAP_FAILED) {
-- 
2.21.3