Index: src/parsers/plan2/FlexLexer.h
--- src/parsers/plan2/FlexLexer.h.orig
+++ src/parsers/plan2/FlexLexer.h
@@ -125,16 +125,22 @@ class yyFlexLexer : public FlexLexer (public)
 
     void yy_switch_to_buffer(yy_buffer_state *new_buffer) override;
     yy_buffer_state *yy_create_buffer(std::istream *s, int size) override;
-    yy_buffer_state *yy_create_buffer(std::istream &s, int size) override;
+    yy_buffer_state *yy_create_buffer(std::istream &s, int size) override {
+        return yy_create_buffer(&s,size);
+    }
     void yy_delete_buffer(yy_buffer_state *b) override;
     void yyrestart(std::istream *s) override;
-    void yyrestart(std::istream &s) override;
+    void yyrestart(std::istream &s) override {
+        yyrestart(&s);
+    }
 
     void yypush_buffer_state(yy_buffer_state *new_buffer);
     void yypop_buffer_state();
 
     int yylex() override;
-    void switch_streams(std::istream &new_in, std::ostream &new_out) override;
+    void switch_streams(std::istream &new_in, std::ostream &new_out) override {
+        switch_streams(&new_in, &new_out);
+    }
     void switch_streams(std::istream *new_in = nullptr, std::ostream *new_out = nullptr) override;
     virtual int yywrap();
 
@@ -147,7 +153,11 @@ class yyFlexLexer : public FlexLexer (public)
     int yyinput();
 
     void yy_load_buffer_state();
-    void yy_init_buffer(yy_buffer_state *b, std::istream &s);
+    void yy_init_buffer(yy_buffer_state *b, std::istream *s);
+
+    void yy_init_buffer(yy_buffer_state *b, std::istream &s) {
+       yy_init_buffer(b, &s);
+    }
     void yy_flush_buffer(yy_buffer_state *b);
 
     int yy_start_stack_ptr;
@@ -162,8 +172,8 @@ class yyFlexLexer : public FlexLexer (public)
     yy_state_type yy_try_NUL_trans(yy_state_type current_state);
     int yy_get_next_buffer();
 
-    std::istream yyin; // input source for default LexerInput
-    std::ostream yyout; // output sink for default LexerOutput
+    std::istream *yyin; // input source for default LexerInput
+    std::ostream *yyout; // output sink for default LexerOutput
 
     // yy_hold_char holds the character lost when yytext is formed.
     char yy_hold_char;
