add extern "C" to use pstrace in C++ applications. renamed global logger

include/libpst.h

@@ -14,6 +14,10 @@
 #include <ucontext.h>
 #include <stdint.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "libpst-types.h"
 
 typedef struct pst_handler pst_handler;
@@ -133,4 +137,8 @@ int pst_unwind_pretty(pst_handler* handler);
  */
 const char* pst_print_pretty(pst_handler* handler);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __LIBPST_EXTERNAL_H_ */