bpf: check llvm version only when used

unetd always includes $(INCLUDE_DIR)/bpf.mk. This file always checks if
the LLVM version is supported in CLANG_VER_VALID. unetd only needs bpf
when UNETD_VXLAN_SUPPORT is set. It fails when UNETD_VXLAN_SUPPORT is
not set and llvm is not installed.

Fix it by only checking the LLVM version when a LLVM toolchain is
available.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
(cherry picked from commit c58177b5dcb3461efef0adefe570dd8a8d966ec4)

diff --git a/include/bpf.mk b/include/bpf.mk
index 7d0cfbd76db45ef17d0778ea817a1f74ebba6035..e43fcad50ce694aa6ac2a847dde2a8cee560641f 100644 (file)
--- a/include/bpf.mk
+++ b/include/bpf.mk
@@ -63,6 +63,7 @@ BPF_CFLAGS := \
        -Wno-unused-label \
        -O2 -emit-llvm -Xclang -disable-llvm-passes
 
+ifneq ($(CONFIG_HAS_BPF_TOOLCHAIN),)
 ifeq ($(DUMP),)
   CLANG_VER:=$(shell $(CLANG) -dM -E - < /dev/null | grep __clang_major__ | cut -d' ' -f3)
   CLANG_VER_VALID:=$(shell [ "$(CLANG_VER)" -ge "$(CLANG_MIN_VER)" ] && echo 1 )
@@ -70,6 +71,7 @@ ifeq ($(DUMP),)
     $(error ERROR: LLVM/clang version too old. Minimum required: $(CLANG_MIN_VER), found: $(CLANG_VER))
   endif
 endif
+endif
 
 define CompileBPF
        $(CLANG) -g -target $(BPF_ARCH)-linux-gnu $(BPF_CFLAGS) $(2) \