[PATCH RFC bpf-next 10/10] arm: include: asm: unified: mask .syntax unified for clang

The samples/bpf reuses linux headers, with clang -emit-llvm,
so this w/a is only for samples/bpf (samples/bpf/Makefile CLANG-bpf).

It allows to build samples/bpf for arm on target board.
In another way clang -emit-llvm generates errors like:

<inline asm>:1:1: error: unknown directive
.syntax unified

I have verified it on clang 5, 6 ,7, 8, 9, 10
as on native platform as for cross-compiling. This decision is
arguable, but it doesn't have impact on samples/bpf so it's easier
just ignore it for clang, at least for now...

Signed-off-by: Ivan Khoronzhuk <redacted>
---
 arch/arm/include/asm/unified.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/unified.h b/arch/arm/include/asm/unified.h
index 1e2c3eb04353..3cf8757b9a14 100644
--- a/arch/arm/include/asm/unified.h
+++ b/arch/arm/include/asm/unified.h

@@ -11,7 +11,11 @@
 #if defined(__ASSEMBLY__)
 	.syntax unified
 #else
-__asm__(".syntax unified");
+
+#ifndef __clang__
+	__asm__(".syntax unified");
+#endif
+
 #endif
 
 #ifdef CONFIG_CPU_V7M

-- 
2.17.1