[Buildroot] [PATCH] libselinux: set PREFIX to generate proper .pc file

[Marcus Folkesson <marcus.folkesson@gmail.com>]

Hi Thomas,

On Sun, Jan 07, 2018 at 03:16:18PM +0100, Thomas Petazzoni wrote:
> Hello,
> 
> Thanks for continuing the work on this topic!
> 
> On Sat,  6 Jan 2018 15:52:49 +0100, Marcus Folkesson wrote:
> > Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
> > ---
> >  package/libselinux/libselinux.mk | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/package/libselinux/libselinux.mk b/package/libselinux/libselinux.mk
> > index 8ac8000de5..bf33da7f75 100644
> > --- a/package/libselinux/libselinux.mk
> > +++ b/package/libselinux/libselinux.mk
> > @@ -43,17 +43,19 @@ LIBSELINUX_MAKE_INSTALL_TARGETS += install-pywrap
> >  # dependencies are broken and result in file truncation errors at link
> >  # time if the Python bindings are built through the same make
> >  # invocation as the rest of the library.
> > +# DESTDIR is needed during the compile to compute library and header paths.
> >  define LIBSELINUX_BUILD_PYTHON_BINDINGS
> >  	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) \
> >  		$(LIBSELINUX_MAKE_OPTS) DESTDIR=$(STAGING_DIR) swigify pywrap
> >  endef
> >  endif # python || python3
> >  
> > +# DESTDIR is needed during the compile to compute library and header paths.
> >  define LIBSELINUX_BUILD_CMDS
> >  	# DESTDIR is needed during the compile to compute library and
> >  	# header paths.
> >  	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) \
> > -		$(LIBSELINUX_MAKE_OPTS) DESTDIR=$(STAGING_DIR) all
> > +		$(LIBSELINUX_MAKE_OPTS) DESTDIR=$(STAGING_DIR) PREFIX=/usr all
> >  	$(LIBSELINUX_BUILD_PYTHON_BINDINGS)
> >  endef
> 
> How can this work without passing PREFIX=/usr also at install time ?
> (Same question for libsemanage and libsepol).

If not PREFIX is passed, it get the value of $(DESTDIR)/usr, which I
think is correct?

If PREFIX=/usr at install time, it tries to install on the host
system.

I guess autotools would have done a better job with DESTDIR and PREFIX.

What I can tell, the libselinux.pc is the only target that make use of
PREFIX during compile time.

But maybe I should set PREFIX explicitly to $(XXXXX_DIR)/usr during
installation just for clarity?

From libselinux/src/Makefile:
PREFIX ?= $(DESTDIR)/usr


> 
> Thanks,
> 
> Thomas
> -- 
> Thomas Petazzoni, CTO, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com


Best regards
Marcus Folkesson