diff --git a/externals/simplecpp/simplecpp.cpp b/externals/simplecpp/simplecpp.cpp
index 7afc17ab735..47e674837ba 100644
--- a/externals/simplecpp/simplecpp.cpp
+++ b/externals/simplecpp/simplecpp.cpp
@@ -275,8 +275,10 @@ class simplecpp::TokenList::Stream {
         return ch;
     }
 
-    unsigned char peekChar() {
-        auto ch = static_cast<unsigned char>(peek());
+    int peekChar() {
+        int ch = peek();
+        if (ch == EOF)
+            return ch;
 
         // For UTF-16 encoded files the BOM is 0xfeff/0xfffe. If the
         // character is non-ASCII character then replace it with 0xff
@@ -285,7 +287,7 @@ class simplecpp::TokenList::Stream {
             const auto ch2 = static_cast<unsigned char>(peek());
             unget();
             const int ch16 = makeUtf16Char(ch, ch2);
-            ch = static_cast<unsigned char>(((ch16 >= 0x80) ? 0xff : ch16));
+            ch = (ch16 >= 0x80) ? 0xff : ch16;
         }
 
         // Handling of newlines..
@@ -598,7 +600,7 @@ std::string simplecpp::TokenList::stringify(bool linenrs) const
     return ret.str();
 }
 
-static bool isNameChar(unsigned char ch)
+static bool isNameChar(int ch)
 {
     return std::isalnum(ch) || ch == '_' || ch == '$';
 }
@@ -635,10 +637,10 @@ static bool isStringLiteralPrefix(const std::string &str)
            str == "R" || str == "uR" || str == "UR" || str == "LR" || str == "u8R";
 }
 
-void simplecpp::TokenList::lineDirective(unsigned int fileIndex, unsigned int line, Location &location)
+void simplecpp::TokenList::lineDirective(unsigned int fileIndex_, unsigned int line, Location &location)
 {
-    if (fileIndex != location.fileIndex || line >= location.line) {
-        location.fileIndex = fileIndex;
+    if (fileIndex_ != location.fileIndex || line >= location.line) {
+        location.fileIndex = fileIndex_;
         location.line = line;
         return;
     }
@@ -771,8 +773,21 @@ void simplecpp::TokenList::readfile(Stream &stream, const std::string &filename,
                     ch = stream.readChar();
                 }
                 stream.ungetChar();
-                push_back(new Token(currentToken, location));
-                location.adjust(currentToken);
+                std::string::size_type pos = 0;
+                unsigned int spliced = 0;
+                while ((pos = currentToken.find('\\', pos)) != std::string::npos) {
+                    if (pos + 1 < currentToken.size() && currentToken[pos + 1] == '\n') {
+                        currentToken.erase(pos, 2);
+                        ++spliced;
+                    } else {
+                        ++pos;
+                    }
+                }
+                if (!currentToken.empty()) {
+                    push_back(new Token(currentToken, location));
+                    location.adjust(currentToken);
+                }
+                location.line += spliced;
                 continue;
             }
         }
@@ -1739,6 +1754,9 @@ namespace simplecpp {
             return tok;
         }
 
+        /**
+         * @throws Error thrown in case of __VA_OPT__ issues
+         */
         bool parseDefine(const Token *nametoken) {
             nameTokDef = nametoken;
             variadic = false;
@@ -2201,6 +2219,8 @@ namespace simplecpp {
             }
 
             output.push_back(newMacroToken(tok->str(), loc, true, tok));
+            if (it != macros.end())
+                output.back()->markExpandedFrom(&it->second);
             return tok->next;
         }
 
@@ -3379,6 +3399,17 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
             }
             output.clear();
             return;
+        } catch (const simplecpp::Macro::Error& e) {
+            if (outputList) {
+                simplecpp::Output err{
+                    Output::DUI_ERROR,
+                    {},
+                    e.what
+                };
+                outputList->emplace_back(std::move(err));
+            }
+            output.clear();
+            return;
         }
     }
 
@@ -3507,14 +3538,14 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
                         else
                             it->second = macro;
                     }
-                } catch (const std::runtime_error &) {
+                } catch (const std::runtime_error &err) {
                     if (outputList) {
-                        simplecpp::Output err{
+                        simplecpp::Output out{
                             Output::SYNTAX_ERROR,
                             rawtok->location,
-                            "Failed to parse #define"
+                            std::string("Failed to parse #define, ") + err.what()
                         };
-                        outputList->emplace_back(std::move(err));
+                        outputList->emplace_back(std::move(out));
                     }
                     output.clear();
                     return;
@@ -3671,7 +3702,7 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
                             bool closingAngularBracket = false;
                             if (tok) {
                                 const std::string &sourcefile = rawtokens.file(rawtok->location);
-                                const bool systemheader = (tok && tok->op == '<');
+                                const bool systemheader = tok->op == '<';
                                 std::string header;
 
                                 if (systemheader) {
diff --git a/externals/simplecpp/simplecpp.h b/externals/simplecpp/simplecpp.h
index d499b132b69..f29166ff061 100644
--- a/externals/simplecpp/simplecpp.h
+++ b/externals/simplecpp/simplecpp.h
@@ -174,9 +174,9 @@ namespace simplecpp {
         bool isOneOf(const char ops[]) const;
         bool startsWithOneOf(const char c[]) const;
         bool endsWithOneOf(const char c[]) const;
-        static bool isNumberLike(const std::string& str) {
-            return std::isdigit(static_cast<unsigned char>(str[0])) ||
-                   (str.size() > 1U && (str[0] == '-' || str[0] == '+') && std::isdigit(static_cast<unsigned char>(str[1])));
+        static bool isNumberLike(const std::string& s) {
+            return std::isdigit(static_cast<unsigned char>(s[0])) ||
+                   (s.size() > 1U && (s[0] == '-' || s[0] == '+') && std::isdigit(static_cast<unsigned char>(s[1])));
         }
 
         TokenString macro;
@@ -213,6 +213,9 @@ namespace simplecpp {
         bool isExpandedFrom(const Macro* m) const {
             return mExpandedFrom.find(m) != mExpandedFrom.end();
         }
+        void markExpandedFrom(const Macro* m) {
+            mExpandedFrom.insert(m);
+        }
 
         void printAll() const;
         void printOut() const;
@@ -376,7 +379,7 @@ namespace simplecpp {
         const std::string& file(const Location& loc) const;
 
     private:
-        TokenList(const unsigned char* data, std::size_t size, std::vector<std::string> &filenames, const std::string &filename, OutputList *outputList, int unused);
+        TokenList(const unsigned char* data, std::size_t size, std::vector<std::string> &filenames, const std::string &filename, OutputList *outputList, int /*unused*/);
 
         void combineOperators();
 
@@ -396,7 +399,7 @@ namespace simplecpp {
         void constFoldQuestionOp(Token *&tok1);
 
         std::string readUntil(Stream &stream, const Location &location, char start, char end, OutputList *outputList);
-        void lineDirective(unsigned int fileIndex, unsigned int line, Location &location);
+        void lineDirective(unsigned int fileIndex_, unsigned int line, Location &location);
 
         const Token* lastLineTok(int maxsize=1000) const;
         const Token* isLastLinePreprocessor(int maxsize=1000) const;