Version script was synced from kernel tree but not enabled in Makefile.
Enable it same way it's done in kernel tree.
% readelf -s --wide src/libbpf.so | grep -Eo '[^ ]+@LIBBPF_.*' | \
cut -d@ -f 3 | sort | uniq -c
121 LIBBPF_0.0.1
29 LIBBPF_0.0.2
Signed-off-by: Andrey Ignatov <rdna@fb.com>
OBJDIR was not specified for libbpf.pc. It works by default since
default value of OBJDIR is current directory, but breaks as soon as
OBJDIR is set to some other directory:
% OBJDIR=build DESTDIR=root make install
...
ar rcs build/libbpf.a build/bpf.o build/btf.o build/libbpf.o
build/libbpf_errno.o build/netlink.o build/nlattr.o build/str_error.o
build/libbpf_probes.o build/bpf_prog_linfo.o build/xsk.o
cc -shared -lelf build/bpf.o build/btf.o build/libbpf.o build/libbpf_errno.o
build/netlink.o build/nlattr.o build/str_error.o build/libbpf_probes.o
build/bpf_prog_linfo.o build/xsk.o -o build/libbpf.so
make: *** No rule to make target `libbpf.pc', needed by `all'. Stop.
Fix it.
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Introduce multiple improvements to Makefile to make the build more
flexible and support install:
* Support overriding CFLAGS by user but keep required flags in place.
ALL_FLAGS is used in Makefile as recommended in [1].
* Add additional BUILD_SHARED flag to build dynamically linked flavor of
the library. If the flag is set, -fPIC is also passed to make it
possible to build .so.
* Support building in a separate directory provided by OBJDIR variable.
* Add multiple install targets. By default the library itself and libbpf
headers are installed (install target). UAPI headers can be optionally
installed by user.
* All installation paths, including PREFIX, library and include
directories can be overridden. UAPI can be made different from include
directory for libbpf headers. That makes it possible to keep latest
<linux/bpf.h> in a place that doesn't conflict with the one installed
e.g. by kernel-headers package and use it in user's build system.
* Support DESTDIR (see [2]).
* Support overriding LDFLAGS.
* Use utilities such as rm directly as recommended in [3].
* Use compiler and related programs (such as ar) via make variables as
recommended in [3].
* In clean rule remove all possible build artifacts not to rely on passed
options (e.g. if build was done w/ BUILD_SHARED, but clean w/o it).
* Document new build options in README.
[1] https://www.gnu.org/software/make/manual/html_node/Command-Variables.html#Command-Variables
[2] https://www.gnu.org/prep/standards/html_node/DESTDIR.html
[3] https://www.gnu.org/software/make/manual/html_node/Utilities-in-Makefiles.html#Utilities-in-Makefiles
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Andrey Ignatov