These changes allow AEL to better check ${} constructs within $[...], that are concatenated with text.

I modified and added rules in ast_expr2.fl to better handle
the concatenations.

I added some default routines to ast_expr2.y so the standalone would
compile. It also looks like I haven't run this thru bison since 2.1, so
it's good to get this updated.

The Makefile has comments added now for check_expr2 and check_expr to
explain what they are for, and how to run them. 

The testexpr2s stuff has been removed, in favor of check_expr2.

expr2.testinput has been updated to include the two expressions
that inspired these changes (from mcnobody on #asterisk this morning)
The regression has been run and all looks well.



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@179807 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/ast_expr2.fl

@@ -158,6 +158,12 @@ HIBIT           [\x80-\xff]
 		return TOKEN;
 	}
 
+([a-zA-Z0-9\.';\\_^#@]|{HIBIT}|($[^{]))+\$\{	{
+		curlycount = 0;
+		BEGIN(var);
+		yymore();
+	}
+
 
 <var>[^{}]*\}	{
 		curlycount--;
@@ -182,6 +188,12 @@ HIBIT           [\x80-\xff]
 		return TOKEN;
 	}
 	
+<trail>[^-\t\r \n$():?%/+=*<>!|&]*\$\{	{
+		curlycount = 0;
+		BEGIN(var);
+		yymore();
+	}
+	
 <trail>[-\t\r \n$():?%/+=*<>!|&]	{
 		char c = yytext[yyleng-1];
 		BEGIN(0);
@@ -191,12 +203,6 @@ HIBIT           [\x80-\xff]
 		return TOKEN;
 	}
 	
-<trail>\$\{	{
-		curlycount = 0;
-		BEGIN(var);
-		yymore();
-	}
-	
 <trail><<EOF>>	{
 		BEGIN(0);
 		SET_COLUMNS;