lib: mbedtls: CMakeLists.txt: fix a typo for CFLAGS
CMAKE_C_CFLAGS -> CMAKE_C_FLAGS, this avoids C_FLAGS from environment
being overridden.
@@ -154,7 +154,7 @@ string(REGEX MATCH "Clang" CMAKE_COMPILER_IS_CLANG "${CMAKE_C_COMPILER_ID}")
include(CheckCCompilerFlag)
-set(CMAKE_C_FLAGS "${CMAKE_C_CFLAGS} -std=c99")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99")
if(CMAKE_COMPILER_IS_GNU)
# some warnings we want are not available with old GCC versions
