cmake: make "-no-pie" optional

The recent linux distros already support PIE so it shouldn't be a
problem to remove "-no-pie". To avoid issue#782, we make "-no-pie"
optional and enable it by default. For the distro with PIE luajit,
just add the following build option:

   -DENABLE_NO_PIE=OFF

Then, bcc-lua will be built with PIE support.

Signed-off-by: Gary Lin <[email protected]>

CMakeLists.txt

@@ -38,6 +38,8 @@ endif()
 # $ cmake -DKERNEL_INCLUDE_DIRS=/tmp/headers/include/ ...
 include_directories(${KERNEL_INCLUDE_DIRS})
 
+option(ENABLE_NO_PIE "Build bcc-lua without PIE" ON)
+
 include(cmake/GetGitRevisionDescription.cmake)
 include(cmake/version.cmake)
 include(CMakeDependentOption)

cmake/FindCompilerFlag.cmake

@@ -1,6 +1,8 @@
 # Copyright (c) 2017 Facebook, Inc.
 # Licensed under the Apache License, Version 2.0 (the "License")
 
+if (ENABLE_NO_PIE)
+
 if (CMAKE_C_COMPILER_ID MATCHES "Clang")
  set(COMPILER_NOPIE_FLAG "-nopie")
 else()
@@ -16,6 +18,8 @@ else()
  set(CMAKE_REQUIRED_FLAGS "${_backup_c_flags}")
 endif()
 
+endif(ENABLE_NO_PIE)
+
 # check whether reallocarray availability
 # this is used to satisfy reallocarray usage under src/cc/libbpf/
 CHECK_CXX_SOURCE_COMPILES(