[PATCH] iio: tools: Use proper macro to detect _Float16 support

["Ivan A. Melnikov" <iv@altlinux.org>]

__FLT16_MAX__ is an internal compiler macro. GCC defines it if
_Float16 is supported by the target in general, but the support
may depend on the exact target options. For example, on i586
without -msse2 I get the following error from GCC15:

  iio_generic_buffer.c: In function 'print2byte':
  iio_generic_buffer.c:141:17: error: invalid conversion from type '_Float16' without option '-msse2'
    141 |                 printf("%05f ", ((float)converter.f + info->offset) * info->scale);
        |                 ^~~~~~

To fix that, use the public macro without double underscores.

Fixes: cdd445d4b2a9 ("iio: tools: Add support for floating-point types in buffer scan elements")
Signed-off-by: Ivan A. Melnikov <iv@altlinux.org>
---
 tools/iio/iio_generic_buffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/iio/iio_generic_buffer.c b/tools/iio/iio_generic_buffer.c
index 000193612aad..9ea93984e0e9 100644
--- a/tools/iio/iio_generic_buffer.c
+++ b/tools/iio/iio_generic_buffer.c
@@ -131,7 +131,7 @@ static void print2byte(uint16_t input, struct iio_channel_info *info)
 		printf("%05f ", ((float)input + info->offset) * info->scale);
 		break;
 	case 'f': {
-#if defined(__FLT16_MAX__)
+#if defined(FLT16_MAX)
 		union {
 			uint16_t u;
 			_Float16 f;
-- 
2.50.1