[SOLVED] When building using a Makefile, O2 and g are being added automatically

Andy Alt · 11-13-2018, 06:29 PM

On Debian 9, when I build this program using make, -g and O2 are being added to the gcc flags automatically. If I manually add -g and -O0 on this line (and re-run automake), it appears 2 times for each file during the build process. So during the build I'd see.. "-g -g -O2 -O0"

If I use `CFLAGS="-O0 -g" ../configure' then the "duplicates" go away.

My goal is to specify any desired flags in Makefile.am and not have any appear from nowhere.

I'm the maintainer for the program, btw.

There's a "Travis" build log at https://travis-ci.org/theimpossiblea...454774151#L553

ehartman · 11-14-2018, 02:11 PM

Quote:

Originally Posted by Andy Alt

On Debian 9, when I build this program using make, -g and O2 are being added to the gcc flags automatically.

As far as I remember "make" uses some default value for CFLAGS if the makefile doesn't supply one itself. So just define any value for CFLAGS yourself in the makefile or define it into the environment (make will pick up that value too).

GazL · 11-14-2018, 03:46 PM

I suspect the default is coming from the AC_PROG_CC macro in configure.ac

https://www.gnu.org/software/autocon...-Compiler.html

Quote:

If you do not like the default insert the line ‘: ${CFLAGS=""}’ after AC_INIT and before AC_PROG_CC to select an empty default instead.

Give that a go and see how you get on.

Andy Alt · 11-15-2018, 10:29 PM

Quote:

insert the line ‘: ${CFLAGS=""}’ after AC_INIT and before AC_PROG_CC

That worked!

Just for the record, before I added that line, I tried removing AC_PROG_CC but the flags still showed up (so they are apparently coming from another source as well).

Andy Alt · 06-29-2019, 01:10 AM

This thread from the GNU autoconf archive has some extra, relevant information about this topic.