Disable EQUS expansion for raw symbols (by parsing them as strings) (#1648)

test/asm/raw-string-symbols.asm

@@ -0,0 +1,34 @@
+opt Wno-unmapped-char
+
+def hello equs "world"
+def name equs "hello"
+println "{name}"
+println #name
+assert !strcmp(strsub(#name, 1, 4), "hell")
+assert strlen(#hello) == charlen(#hello)
+assert strlen("{hello}") == 5
+
+def multi equs """the	quick
+brown	fox"""
+println #multi
+
+def char equs "A"
+def n = #char
+println n
+def n = (#char)
+println n
+def n = 1 + #char
+println n
+assert #char == $41
+
+def fmt equs "%s %s %d"
+println strfmt(#fmt, #name, #hello, (#char))
+
+purge #name
+assert !def(name) && !def(#name) && def(hello)
+
+section "test", rom0
+#label:
+db #hello
+dw #hello
+dw BANK(#label), #label