Re: [hackers] [dmenu][PATCH] don't mangle CPPFLAGS with CFLAGS

From: NRK <nrk_AT_disroot.org>
Date: Tue, 26 Jul 2022 23:57:04 +0600

On Mon, Jul 04, 2022 at 03:01:35PM +0600, NRK wrote:
> currently, doing something like the following would fail to build:
>
> $ make CFLAGS="-O3 -march=native"
>
> this is because CPPFLAGS get mangled with CFLAGS and so changing CFLAGS
> kills the build.
>
> similarly it's conventional to have library flags in LDLIBS, so that
> user can change LDFLAGS to add "-flto" or other flags they might want
> without the build unnecessarily failing.
> ---
>
> P.S: Could also drop `-std=c99` from CFLAGS and set CC to c99. But
> didn't do that since it wasn't needed for my goal of being able to do
> something like the following:
>
> $ make CFLAGS="-O3 -flto" LDFLAGS="-O3 -flto"
>
> Makefile | 8 +++++---
> config.mk | 6 +++---
> 2 files changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index a03a95c..8d25ad0 100644
> --- a/Makefile
> +++ b/Makefile
> _AT_@ -11,11 +11,13 @@ all: options dmenu stest
> options:
> _AT_echo dmenu build options:
> _AT_echo "CFLAGS = $(CFLAGS)"
> + _AT_echo "CPPFLAGS = $(CPPFLAGS)"
> _AT_echo "LDFLAGS = $(LDFLAGS)"
> + _AT_echo "LDLIBS = $(LDLIBS)"
> _AT_echo "CC = $(CC)"
>
> .c.o:
> - $(CC) -c $(CFLAGS) $<
> + $(CC) -c $(CPPFLAGS) $(CFLAGS) $<
>
> config.h:
> cp config.def.h $_AT_
> _AT_@ -23,10 +25,10 @@ config.h:
> $(OBJ): arg.h config.h config.mk drw.h
>
> dmenu: dmenu.o drw.o util.o
> - $(CC) -o $_AT_ dmenu.o drw.o util.o $(LDFLAGS)
> + $(CC) -o $_AT_ dmenu.o drw.o util.o $(LDFLAGS) $(LDLIBS)
>
> stest: stest.o
> - $(CC) -o $_AT_ stest.o $(LDFLAGS)
> + $(CC) -o $_AT_ stest.o $(LDFLAGS) $(LDLIBS)
>
> clean:
> rm -f dmenu stest $(OBJ) dmenu-$(VERSION).tar.gz
> diff --git a/config.mk b/config.mk
> index b0bd246..a513b74 100644
> --- a/config.mk
> +++ b/config.mk
> _AT_@ -24,9 +24,9 @@ INCS = -I$(X11INC) -I$(FREETYPEINC)
> LIBS = -L$(X11LIB) -lX11 $(XINERAMALIBS) $(FREETYPELIBS)
>
> # flags
> -CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700 -D_POSIX_C_SOURCE=200809L -DVERSION=\"$(VERSION)\" $(XINERAMAFLAGS)
> -CFLAGS = -std=c99 -pedantic -Wall -Os $(INCS) $(CPPFLAGS)
> -LDFLAGS = $(LIBS)
> +CPPFLAGS = $(INCS) -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700 -D_POSIX_C_SOURCE=200809L -DVERSION=\"$(VERSION)\" $(XINERAMAFLAGS)
> +CFLAGS = -std=c99 -pedantic -Wall -Os
> +LDLIBS = $(LIBS)
>
> # compiler and linker
> CC = cc
> --
> 2.35.1
>
>

Any comment on this? Or any specific reason for deviating from the
conventional approach and mangling `CFLAGS` and `CPPFLAGS`?

- NRK
Received on Tue Jul 26 2022 - 19:57:04 CEST