bpftool: Fix failure with static linkage

When building perf with static linkage:

  make O=/build LDFLAGS="-static" -C tools/perf VF=1 DEBUG=1
  ...
  LINK    /build/util/bpf_skel/.tmp/bootstrap/bpftool
  /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/13/../../../x86_64-linux-gnu/libelf.a(elf_compress.o): in function `__libelf_compress':
  (.text+0x113): undefined reference to `ZSTD_createCCtx'
  /usr/bin/ld: (.text+0x2a9): undefined reference to `ZSTD_compressStream2'
  /usr/bin/ld: (.text+0x2b4): undefined reference to `ZSTD_isError'
  /usr/bin/ld: (.text+0x2db): undefined reference to `ZSTD_freeCCtx'
  /usr/bin/ld: (.text+0x5a0): undefined reference to `ZSTD_compressStream2'
  /usr/bin/ld: (.text+0x5ab): undefined reference to `ZSTD_isError'
  /usr/bin/ld: (.text+0x6b9): undefined reference to `ZSTD_freeCCtx'
  /usr/bin/ld: (.text+0x835): undefined reference to `ZSTD_freeCCtx'
  /usr/bin/ld: (.text+0x86f): undefined reference to `ZSTD_freeCCtx'
  /usr/bin/ld: (.text+0x91b): undefined reference to `ZSTD_freeCCtx'
  /usr/bin/ld: (.text+0xa12): undefined reference to `ZSTD_freeCCtx'
  /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/13/../../../x86_64-linux-gnu/libelf.a(elf_compress.o): in function `__libelf_decompress':
  (.text+0xbfc): undefined reference to `ZSTD_decompress'
  /usr/bin/ld: (.text+0xc04): undefined reference to `ZSTD_isError'
  /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/13/../../../x86_64-linux-gnu/libelf.a(elf_compress.o): in function `__libelf_decompress_elf':
  (.text+0xd45): undefined reference to `ZSTD_decompress'
  /usr/bin/ld: (.text+0xd4d): undefined reference to `ZSTD_isError'
  collect2: error: ld returned 1 exit status

Building bpftool with static linkage also fails with the same errors:

  make O=/build -C tools/bpf/bpftool/ V=1

To fix the issue, explicitly link libzstd.

Signed-off-by: Leo Yan <[email protected]>
Tested-by: Namhyung Kim <[email protected]>

tools/bpf/bpftool/Makefile

@@ -130,8 +130,8 @@ include $(FEATURES_DUMP)
 endif
 endif
 
-LIBS = $(LIBBPF) -lelf -lz
-LIBS_BOOTSTRAP = $(LIBBPF_BOOTSTRAP) -lelf -lz
+LIBS = $(LIBBPF) -lelf -lz -lzstd
+LIBS_BOOTSTRAP = $(LIBBPF_BOOTSTRAP) -lelf -lz -lzstd
 ifeq ($(feature-libcap), 1)
 CFLAGS += -DUSE_LIBCAP
 LIBS += -lcap