[PATCH v2] linux-user: Fix clang warning for nios2-linux-user code

[Peter Maydell]

The clang in Ubuntu 18.04 (10.0.0-4ubuntu1) produces a warning
on the code added in commit f5ef0e518d03 where we use a
shifted expression in a boolean context:

../../linux-user/elfload.c:2423:16: error: converting the result of '<<' to a 
boolean always evaluates to true [-Werror,-Wtautological-constant-compare]
    } else if (LO_COMMPAGE) {
               ^
../../linux-user/elfload.c:1102:22: note: expanded from macro 'LO_COMMPAGE'
#define LO_COMMPAGE  TARGET_PAGE_SIZE
                     ^
/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/include/exec/cpu-all.h:231:31: note: 
expanded from macro 'TARGET_PAGE_SIZE'
#define TARGET_PAGE_SIZE   (1 << TARGET_PAGE_BITS)
                              ^
1 error generated.

The warning is bogus because whether LO_COMMPAGE is zero or not
depends on compile-time ifdefs; shut the compiler up by adding
an explicit comparison to zero.

Fixes: f5ef0e518d0331 ("linux-user/nios2: Map a real kuser page")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
v1->v2: fix sense of comparison (oops!)

 linux-user/elfload.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 329b2375ef1..d3274edfdb7 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2420,7 +2420,7 @@ static void pgb_static(const char *image_name, abi_ulong 
orig_loaddr,
         } else {
             offset = -(HI_COMMPAGE & -align);
         }
-    } else if (LO_COMMPAGE) {
+    } else if (LO_COMMPAGE != 0) {
         loaddr = MIN(loaddr, LO_COMMPAGE & -align);
     }
 
-- 
2.25.1