[PATCH bpf v2] tools/bpf: properly account for libbfd variations

[Stanislav Fomichev <sdf@google.com>]

On some platforms, in order to link against libbfd, we need to
link against liberty and even possibly libz. Account for that
in the bpftool Makefile. We now have proper feature detection
for each case, so handle each one separately.

See recent commit 14541b1e7e72 ("perf build: Don't unconditionally link the
libbfd feature test to -liberty and -lz") where I fixed feature
detection.

v2 (addressed Jakub's nits):
  * better syntax for 'else ifeq'
  * no space between ifeq args

Fixes: 29a9c10e4110 ("bpftool: make libbfd optional")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/bpf/bpftool/Makefile | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 492f0f24e2d3..fbf7e62a5b86 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -93,9 +93,16 @@ BFD_SRCS = jit_disasm.c
 SRCS = $(filter-out $(BFD_SRCS),$(wildcard *.c))
 
 ifeq ($(feature-libbfd),1)
+  LIBS += -lbfd -ldl -lopcodes
+else ifeq ($(feature-libbfd-liberty),1)
+  LIBS += -lbfd -ldl -lopcodes -liberty
+else ifeq ($(feature-libbfd-liberty-z),1)
+  LIBS += -lbfd -ldl -lopcodes -liberty -lz
+endif
+
+ifneq ($(filter -lbfd,$(EXTLIBS)),)
 CFLAGS += -DHAVE_LIBBFD_SUPPORT
 SRCS += $(BFD_SRCS)
-LIBS += -lbfd -lopcodes
 endif
 
 OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
-- 
2.20.1.97.g81188d93c3-goog