[ndctl PATCH] util/size.h: Fix build error for GCC < 10

[Vaibhav Jain <vaibhav@linux.ibm.com>]

Building with GCC 8.4.1 results in following build error for 'util/size.c':

../util/size.h:57:16: error: missing binary operator before token "("
   __has_builtin(__builtin_mul_overflow) && \

This is caused due to missing '__has_builtin' preprocessor operator in GCC
versions < 10.0.0. The patch updates the check for CLANG's availability of
__builtin_{mul,add}_overflow to prevent preprocessor from evaluating the
expression "___has_builtin(__builtin_mul_overflow) &&
__has_builtin(__builtin_add_overflow)".

Fixes:10653a171bc0("util/size.h: fix build for older compilers")
Reported-by: Tarun Sahu <tsahu@linux.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
 util/size.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/util/size.h b/util/size.h
index 1cb06690261b..02baa77fe649 100644
--- a/util/size.h
+++ b/util/size.h
@@ -53,11 +53,12 @@ static inline bool is_power_of_2(unsigned long long v)
 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
 #endif
 
-#if __clang__ && \
-    __has_builtin(__builtin_mul_overflow) && \
+#if __clang__
+#if __has_builtin(__builtin_mul_overflow) && \
     __has_builtin(__builtin_add_overflow)
 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
 #endif
+#endif
 
 #if COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW
 
-- 
2.35.1