commit 3980bad87fe18ad9d32914e9d21dba145eba973f
author Tadeusz Struk <tadeusz.struk@intel.com> Wed Apr 04 10:30:01 2018 -0700
committer Tadeusz Struk <tadeusz.struk@intel.com> Fri Apr 06 15:47:38 2018 -0700
tree ed2d0f337adf65570a03057bc7741b52c1e91e64
parent caff7541125892771addc574ecd668aa5a254c4a

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>

configure.ac

diff --git a/configure.ac b/configure.ac
index 81bafda..9a657db 100644
--- a/configure.ac
+++ b/configure.ac
@@ -31,6 +31,7 @@
         [],
         [https://github.com/tpm2-software/tpm2-tss])
 AC_CONFIG_MACRO_DIR([m4])
+${CFLAGS=""}
 AC_PROG_CC
 LT_INIT()
 AM_INIT_AUTOMAKE([foreign
@@ -149,9 +150,10 @@
                             [build with debug info (default is no)])],
             [enable_debug=$enableval],
             [enable_debug=no])
-AS_IF([test "x$enable_debug" = "xyes"], AX_ADD_COMPILER_FLAG([-ggdb3 -O0]))
+AS_IF([test "x$enable_debug" = "xyes"], AX_ADD_COMPILER_FLAG([-ggdb3 -Og]))
 AS_IF([test "x$enable_debug" = "xno"], [AX_ADD_PREPROC_FLAG([-U_FORTIFY_SOURCE])
-                                        AX_ADD_PREPROC_FLAG([-D_FORTIFY_SOURCE=2])])
+                                        AX_ADD_PREPROC_FLAG([-D_FORTIFY_SOURCE=2])
+                                        AX_ADD_COMPILER_FLAG([-g -O2])])
 AX_ADD_LINK_FLAG([-Wl,--no-undefined])
 AX_ADD_LINK_FLAG([-Wl,-z,noexecstack])
 AX_ADD_LINK_FLAG([-Wl,-z,now])