* Handle carriage returns. Fixes NIX-53.

src/libexpr/lexer.l

@@ -21,6 +21,10 @@ static void adjustLoc(YYLTYPE * loc, const char * s, size_t len)
 {
     while (len--) {
        switch (*s++) {
+       case '\r':
+           if (*s == '\n') /* cr/lf */
+               s++;
+           /* fall through */
        case '\n': 
            ++loc->first_line;
            loc->first_column = 1;
@@ -85,8 +89,8 @@ inherit     { return INHERIT; }
 {PATH}      { yylval->t = toATerm(yytext); return PATH; /* !!! alloc */ }
 {URI}       { yylval->t = toATerm(yytext); return URI; /* !!! alloc */ }
 
-[ \t\n]+    /* eat up whitespace */
-\#[^\n]*    /* single-line comments */
+[ \t\r\n]+    /* eat up whitespace */
+\#[^\r\n]*    /* single-line comments */
 \/\*([^*]|\*[^\/])*\*\/  /* long comments */
 
 .           return yytext[0];

src/libexpr/parser.cc

@@ -79,11 +79,16 @@ Expr unescapeStr(const char * s)
         if (c == '\\') {
             assert(*s);
             c = *s++;
-            if (c == 'n') t += "\n";
-            else if (c == 'r') t += "\r";
-            else if (c == 't') t += "\t";
+            if (c == 'n') t += '\n';
+            else if (c == 'r') t += '\r';
+            else if (c == 't') t += '\t';
             else t += c;
         }
+        else if (c == '\r') {
+            /* Normalise CR and CR/LF into LF. */
+            t += '\n';
+            if (*s == '\n') s++; /* cr/lf */
+        }
         else t += c;
     }
     return makeStr(toATerm(t));