fix non-lz4 build of plugin

src/plugin/pctrace.cpp

@@ -10,8 +10,9 @@
 #include <rapidjson/error/en.h>
 #include <fstream>
 #include <iostream>
+#ifdef WITH_LZ4
 #include <lz4frame.h>
-
+#endif
 
 namespace iss {
 namespace plugin {
@@ -19,6 +20,7 @@ namespace plugin {
 using namespace rapidjson;
 using namespace std;
 
+#ifdef WITH_LZ4
 class lz4compress_steambuf: public std::streambuf {
 public:
     lz4compress_steambuf(const lz4compress_steambuf&) = delete;
@@ -86,6 +88,7 @@ private:
     LZ4F_compressionContext_t ctx{ nullptr };
     bool closed{ false };
 };
+#endif
 
 cov::cov(std::string const &filename)
 : instr_if(nullptr)