Makefile: Use CPPFLAGS from the environment

CPPFLAGS is commonly used for preprecessor definitions which
should be used when compiling C and C++ files. In particular,
Debian uses it to pass hardening flags and expects those flags
to be used.

Link: http://lkml.kernel.org/r/1389030985-26657-2-git-send-email-seth.forshee@canonical.com

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
1 file changed