Remove -std=c89 from compiler command line.

We aren't targeting pure C89 any longer and it also upsets GCC on
AArch64 because asm() isn't part of C89.

Change-Id: I0ba299160e2f0c40d9a99ea8df13b4bb33c08163
Reviewed-on: https://boringssl-review.googlesource.com/2800
Reviewed-by: Adam Langley <agl@google.com>

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 40a3465..c7b7044 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,7 +3,7 @@
 project (BoringSSL)
 
 if(CMAKE_COMPILER_IS_GNUCXX OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
-	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wshadow -Werror -ggdb -std=c89")
+	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wshadow -Werror -ggdb")
 	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wshadow -Werror -ggdb -std=c++0x")
 elseif(MSVC)
 	# Disable warnings for implicit integer narrowing.