Allow libdebuginfod to be excluded even if present

libdebuginfod support is currently only configurable by the presence of the library itself.

Unfortunately, when using the static libraries the libdebuginfod dependency gets
propagated to users of bcc (e.g. bpftrace), who would have to require it as well.

Introduce ENABLE_LIBDEBUGINFOD to allow overriding libdebuginfod usage
from above. This allows bcc users to decide for themselves if they want
this dependency.

CMakeLists.txt

@@ -110,6 +110,7 @@ option(ENABLE_EXAMPLES "Build examples" ON)
 option(ENABLE_MAN "Build man pages" ON)
 option(ENABLE_TESTS "Build tests" ON)
 option(RUN_LUA_TESTS "Run lua tests" ON)
+option(ENABLE_LIBDEBUGINFOD "Use libdebuginfod as a source of debug symbols" ON)
 CMAKE_DEPENDENT_OPTION(ENABLE_CPP_API "Enable C++ API" ON "ENABLE_USDT" OFF)
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_SOURCE_DIR}/cmake)

cmake/FindLibDebuginfod.cmake

@@ -48,8 +48,8 @@ FIND_PACKAGE_HANDLE_STANDARD_ARGS(LibDebuginfod DEFAULT_MSG
  LIBDEBUGINFOD_LIBRARIES
  LIBDEBUGINFOD_INCLUDE_DIRS)
 
-if (LIBDEBUGINFOD_FOUND)
+if (LIBDEBUGINFOD_FOUND AND ENABLE_LIBDEBUGINFOD)
  add_definitions(-DHAVE_LIBDEBUGINFOD)
-endif (LIBDEBUGINFOD_FOUND)
+endif (LIBDEBUGINFOD_FOUND AND ENABLE_LIBDEBUGINFOD)
 
 mark_as_advanced(LIBDEBUGINFOD_INCLUDE_DIRS LIBDEBUGINFOD_LIBRARIES)

src/cc/CMakeLists.txt

@@ -9,9 +9,9 @@ include_directories(${CMAKE_CURRENT_SOURCE_DIR}/frontends/b)
 include_directories(${CMAKE_CURRENT_SOURCE_DIR}/frontends/clang)
 include_directories(${LLVM_INCLUDE_DIRS})
 include_directories(${LIBELF_INCLUDE_DIRS})
-if (LIBDEBUGINFOD_FOUND)
+if (LIBDEBUGINFOD_FOUND AND ENABLE_LIBDEBUGINFOD)
  include_directories(${LIBDEBUGINFOD_INCLUDE_DIRS})
-endif (LIBDEBUGINFOD_FOUND)
+endif (LIBDEBUGINFOD_FOUND AND ENABLE_LIBDEBUGINFOD)
 # todo: if check for kernel version
 if (CMAKE_USE_LIBBPF_PACKAGE AND LIBBPF_FOUND)
  include_directories(${LIBBPF_INCLUDE_DIRS})