12.9. Respect CFLAGS

The port must respect CFLAGS. What we mean by this is that the port must not set the value of this variable absolutely, overriding the existing value. Instead, it may append whatever values it needs to the existing value. This is so that build options that affect all ports can be set globally.

If it does not, please add NO_PACKAGE=ignores cflags to the Makefile.

Here is an example of a Makefile respecting CFLAGS. Note the +=:

CFLAGS+= -Wall -Werror

Here is an example which does not respect CFLAGS:

CFLAGS= -Wall -Werror

CFLAGS is defined on FreeBSD systems in /etc/make.conf. The first example appends additional flags to CFLAGS, preserving any system-wide definitions. The second example clobbers anything previously defined.

Remove optimization flags from the third party Makefiles. The system CFLAGS contains system-wide optimization flags. An example from an unmodified Makefile:

CFLAGS= -O3 -funroll-loops -DHAVE_SOUND

Using system optimization flags, the Makefile would look similar to this example:


All FreeBSD documents are available for download at https://download.freebsd.org/ftp/doc/

Questions that are not answered by the documentation may be sent to <freebsd-questions@FreeBSD.org>.
Send questions about this document to <freebsd-doc@FreeBSD.org>.