ECPG: Fix this test case:

int main(void)
{
	exec sql begin declare section;
	int	x, y;
	varchar	a[50], b[50];
	exec sql end declare section;

	return 0;
}

struct varchar_1  { ... }  a _,_  struct varchar_2  { ... }  b ;

The comma in the generated C file is a syntax error.
Make the preprocessor emit ';' if the variable type
for a list of variables is varchar.

No changes in the regression tests.