read_ilang: improve style. NFC.

Co-Authored-By: Alberto Gonzalez <61295559+boqwxp@users.noreply.github.com>

diff --git a/frontends/ilang/ilang_lexer.l b/frontends/ilang/ilang_lexer.l
index e36818e4fc40856a5c44767e12436773d845bec2..62f53d18e69152be49c922d2052e24e53b309aca 100644 (file)
--- a/frontends/ilang/ilang_lexer.l
+++ b/frontends/ilang/ilang_lexer.l
@@ -90,7 +90,7 @@ USING_YOSYS_NAMESPACE
 
 [0-9]+'[01xzm-]*       { rtlil_frontend_ilang_yylval.string = strdup(yytext); return TOK_VALUE; }
 -?[0-9]+               {
-       char *end = NULL;
+       char *end = nullptr;
        long value = strtol(yytext, &end, 10);
        if (end != yytext + strlen(yytext))
                return TOK_INVALID; // literal out of range of long
@@ -146,4 +146,3 @@ USING_YOSYS_NAMESPACE
 void *rtlil_frontend_ilang_avoid_input_warnings() {
        return (void*)&yyinput;
 }
-