pkg/codesearch: add skeleton for code searching tool

Add a clang tool that is used for code indexing (tools/clang/codesearch/).
It follows conventions and build procedure of the declextract tool.

Add pkg/codesearch package that aggregates the info exposed by the clang tools,
and allows doing simple queries:
 - show source code of an entity (function, struct, etc)
 - show entity comment
 - show all entities defined in a source file

Add tools/syz-codesearch wrapper tool that allows to create index for a kernel build,
and then run code queries on it.

1 files changed, 8 insertions, 0 deletions

diff --git a/pkg/codesearch/testdata/query-def-source-close b/pkg/codesearch/testdata/query-def-source-close
new file mode 100644
index 000000000..2a9dcefad
--- /dev/null
+++ b/pkg/codesearch/testdata/query-def-source-close
@@ -0,0 +1,8 @@
+def-source source0.c close no
+
+function close is defined in source0.c:
+
+int close()
+{
+	return 0;
+}