kconfig: expand lefthand side of assignment statement

Make expands the lefthand side of assignment statements.  In fact,
Kbuild relies on it since kernel makefiles mostly look like this:

  obj-$(CONFIG_FOO) += foo.o

Do likewise in Kconfig.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l
index a6cbe2d06d01..25bd2b89fe3f 100644
--- a/scripts/kconfig/zconf.l
+++ b/scripts/kconfig/zconf.l
@@ -114,6 +114,13 @@ n	[A-Za-z0-9_-]
                 yylval.string = text;
                 return T_VARIABLE;
         }
+        ({n}|$)+        {
+                /* this token includes at least one '$' */
+                yylval.string = expand_token(yytext, yyleng);
+                if (strlen(yylval.string))
+                        return T_VARIABLE;
+                free(yylval.string);
+        }
         "="     { BEGIN(ASSIGN_VAL); yylval.flavor = VAR_RECURSIVE; return T_ASSIGN; }
         ":="    { BEGIN(ASSIGN_VAL); yylval.flavor = VAR_SIMPLE; return T_ASSIGN; }
         "+="    { BEGIN(ASSIGN_VAL); yylval.flavor = VAR_APPEND; return T_ASSIGN; }