[U-Boot] [PATCH] tools/Makefile: build host tools with -std=gnu99

[Thomas Petazzoni]

Parts of the code are using C99 constructs (such as variables declared
inside loops), but also GNU extensions (such as typeof), so using
-std=gnu99 is necessary to build with older versions of gcc that don't
default to building with gnu99.

It fixes the following build failure:

./tools/../lib/crc16.c: In function "crc16_ccitt":
./tools/../lib/crc16.c:70:2: error: "for" loop initial declarations are only allowed in C99 mode
  for (int i = 0;  i < len;  i++)
  ^
./tools/../lib/crc16.c:70:2: note: use option -std=c99 or -std=gnu99 to compile your code

when building the host tools with gcc 4.7.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
---
 tools/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/Makefile b/tools/Makefile
index 081383d7a7..d377d85f74 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -254,7 +254,8 @@ HOST_EXTRACFLAGS += -include $(srctree)/include/compiler.h \
 		-I$(srctree)/tools \
 		-DUSE_HOSTCC \
 		-D__KERNEL_STRICT_NAMES \
-		-D_GNU_SOURCE
+		-D_GNU_SOURCE \
+		-std=gnu99
 
 __build:	$(LOGO-y)
 
-- 
2.20.1