How to override dpkg-buildflags CFLAGS?

Question

I have a package with:

$ apt-get source <pkg-name> 

and now I'm trying to build it with:

 $ dpkg-buildpackage -uc -us -j8 

At the beginning of the output is indicated:

 dpkg-buildpackage: export CFLAGS from dpkg-buildflags (origin: vendor): -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Wformat-security dpkg-buildpackage: export CPPFLAGS from dpkg-buildflags (origin: vendor): -D_FORTIFY_SOURCE=2 dpkg-buildpackage: export CXXFLAGS from dpkg-buildflags (origin: vendor): -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Wformat-security dpkg-buildpackage: export FFLAGS from dpkg-buildflags (origin: vendor): -g -O2 dpkg-buildpackage: export LDFLAGS from dpkg-buildflags (origin: vendor): -Wl,-Bsymbolic-functions -Wl,-z,relro 

I would like to redefine these CFLAGS (also, LDFLAGS). I tried to export CFLAGS envvar, just as we do with simple setup, to no avail. How can I override these values?

Answer 1

the package you are trying to rebuild installs (reads: redefines) the FLAGS flag with the stiffness flags obtained from dpkg-buildflags .

if you need to override these flags for your own purposes, you should tell dpkg-buildflags to provide the necessary flags, rather than (simplify) the default values. looking at man dpkg-buildflags , you will find a section on environment variables, especially. see DEB_flag_SET and DEB_flag_APPEND

so this should do the trick (fill in your own FLAGS):

 $ DEB_CPPFLAGS_SET="-I/foo/bar/baz" DEB_CFLAGS_SET="-g -O6" DEB_LDFLAGS_SET="-L/fruzzel/frazzel/" dpkg-buildpackage -uc -us -j8 -rfakeroot