tree ed2d0f337adf65570a03057bc7741b52c1e91e64
parent caff7541125892771addc574ecd668aa5a254c4a
author Tadeusz Struk <tadeusz.struk@intel.com> 1522863001 -0700
committer Tadeusz Struk <tadeusz.struk@intel.com> 1523054858 -0700

build: disable default -O2 flag

To build binaries with debug info the configure script takes
--enable-debug=yes flag (default no). This produces makefiles
with EXTRA_CFLAGS = -Og flag. The problem is that autotools
still produces CFLAGS = -g -O2 by default, which affects
the debug info. To swith off the default optimization flags
we need to set CFLAGS="" before AC_PROG_CC macro, and then
add optimizations to EXTRA_CFLAGS if debug is not enabled.

See:
https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/C-Compiler.html
section: AC_PROG_CC

Fixes: #589

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>