1 files changed, 15 insertions, 5 deletions
diff --git a/zen/legacy_compiler.h b/zen/legacy_compiler.h
index d0b4d3fe..6ce1d765 100644
--- a/zen/legacy_compiler.h
+++ b/zen/legacy_compiler.h
@@ -8,19 +8,25 @@
 #define LEGACY_COMPILER_H_839567308565656789
 
 
+#if !__cpp_lib_erase_if
+#include <vector>
+#include <set>
+#include <map>
+#endif
+
 
+//https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations
+//https://en.cppreference.com/w/User:D41D8CD98F/feature_testing_macros
+//https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html
 namespace std
 {
-//https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html
-//https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations
-
 
+//---------------------------------------------------------------------------------
 
 #if __cpp_lib_span
-    #error get rid of workarounds
+    #error get rid of workaround:
 #endif
 
-//requires C++20! until then, this should suffice...
 template <class T>
 class span
 {
@@ -51,8 +57,12 @@ private:
     const size_t size_;
     T* const data_;
 };
+
+//---------------------------------------------------------------------------------
+
 }
 
+
 namespace zen
 {
 double from_chars(const char* first, const char* last);