Fix rgbasm -s not overriding a previous -s

src/asm/main.cpp

@@ -289,7 +289,7 @@ static void parseArg(int ch, char *arg) {
 		if (localOptions.stateFileSpecs.find(name) != localOptions.stateFileSpecs.end()) {
 			warnx("Overriding state file \"%s\"", name);
 		}
-		localOptions.stateFileSpecs.emplace(name, std::move(features));
+		localOptions.stateFileSpecs[name] = std::move(features);
 		break;
 	}
 

test/asm/state-override.asm

@@ -0,0 +1,2 @@
+DEF s EQUS "hello"
+DEF n EQU 42

test/asm/state-override.err

@@ -0,0 +1 @@
+warning: Overriding state file "-"

test/asm/state-override.flags

@@ -0,0 +1 @@
+-s equs:- -s equ:-

test/asm/state-override.out

@@ -0,0 +1,4 @@
+; File generated by rgbasm
+
+; Numeric constants
+def n equ $2a