[PATCH] linux-user: avoid -Werror=int-in-bool-context

[Paolo Bonzini <pbonzini@redhat.com>]

linux-user is failing to compile on Fedora 43:

../linux-user/strace.c:57:66: error: enum constant in boolean context [-Werror=int-in-bool-context]
   57 | #define FLAG_BASIC(V, M, N)      { V, M | QEMU_BUILD_BUG_ON_ZERO(!(M)), N }

The warning does not seem to useful and we could even disable it, but
the workaround is simple in this case.

Cc: qemu-stable@nongnu.org
Cc: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 linux-user/strace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/linux-user/strace.c b/linux-user/strace.c
index 1233ebceb08..758c5d32b6c 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -54,7 +54,7 @@ struct flags {
 };
 
 /* No 'struct flags' element should have a zero mask. */
-#define FLAG_BASIC(V, M, N)      { V, M | QEMU_BUILD_BUG_ON_ZERO(!(M)), N }
+#define FLAG_BASIC(V, M, N)      { V, M | QEMU_BUILD_BUG_ON_ZERO((M) == 0), N }
 
 /* common flags for all architectures */
 #define FLAG_GENERIC_MASK(V, M)  FLAG_BASIC(V, M, #V)
-- 
2.51.0