As GCC manual says, -D option defines a macro as 1, if =<value> is omitted.

  -D <name>
      Predefine <name> as a macro, with definition 1.

The same applied with Clang, too.

In the context of -D option, =1 is always redundant.

Change-Id: I487489a1ea3eb51e734741619c1e65dab1420bc4
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>