[PATCH v3 2/2] bpf: makefiles: do not generate empty vmlinux.h

[Changbin Du <changbin.du@gmail.com>]

Remove the empty vmlinux.h if bpftool failed to dump btf info.
The empty vmlinux.h can hide real error when reading output
of make.

This is done by adding .DELETE_ON_ERROR special target in related
makefiles.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
---
 tools/bpf/bpftool/Makefile           | 3 +++
 tools/testing/selftests/bpf/Makefile | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 787b857d3fb5..313fd1b09189 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -289,3 +289,6 @@ FORCE:
 .PHONY: all FORCE bootstrap clean install-bin install uninstall
 .PHONY: doc doc-clean doc-install doc-uninstall
 .DEFAULT_GOAL := all
+
+# Delete partially updated (corrupted) files on error
+.DELETE_ON_ERROR:
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index c22c43bbee19..205e8c3c346a 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -626,3 +626,6 @@ EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) $(SCRATCH_DIR) $(HOST_SCRATCH_DIR)	\
 			       liburandom_read.so)
 
 .PHONY: docs docs-clean
+
+# Delete partially updated (corrupted) files on error
+.DELETE_ON_ERROR:
-- 
2.37.2