fix build issue for llvm 5.0.1

Fix issue #1502.
A few cmake version checking greater than 5 includes 5.0.1
which results in compilation failure. Change version checking
to explicitly equal to or greater than version 6.
Signed-off-by: Yonghong Song <yhs@fb.com>

cmake/clang_libs.cmake

@@ -8,7 +8,7 @@ list(FIND LLVM_AVAILABLE_LIBS "LLVMCoroutines" _llvm_coroutines)
 if (${_llvm_coroutines} GREATER -1)
   list(APPEND llvm_raw_libs coroutines)
 endif()
-if (${LLVM_PACKAGE_VERSION} VERSION_GREATER "5")
+if (${LLVM_PACKAGE_VERSION} VERSION_EQUAL 6 OR ${LLVM_PACKAGE_VERSION} VERSION_GREATER 6)
   list(APPEND llvm_raw_libs bpfasmparser)
   list(APPEND llvm_raw_libs bpfdisassembler)
 endif()

src/cc/CMakeLists.txt

@@ -29,7 +29,7 @@ set_target_properties(bpf-shared PROPERTIES VERSION ${REVISION_LAST} SOVERSION 0
 set_target_properties(bpf-shared PROPERTIES OUTPUT_NAME bpf)
 
 set(bcc_common_sources bpf_common.cc bpf_module.cc exported_files.cc)
-if (${LLVM_PACKAGE_VERSION} VERSION_GREATER "5")
+if (${LLVM_PACKAGE_VERSION} VERSION_EQUAL 6 OR ${LLVM_PACKAGE_VERSION} VERSION_GREATER 6)
   set(bcc_common_sources ${bcc_common_sources} bcc_debug.cc)
 endif()