add support for linux_riscv64 and freestanding_riscv64

src/main.cpp

@@ -3245,6 +3245,15 @@ int main(int arg_count, char const **arg_ptr) {
 		}
 	}
 
+	// NOTE(laytan): on riscv64 we want to enforce some features.
+	if (build_context.metrics.arch == TargetArch_riscv64) {
+		String disabled;
+		if (!check_target_feature_is_enabled(str_lit("64bit,f,d,m"), &disabled)) { // 64bit, floats, doubles, integer multiplication.
+			gb_printf_err("missing required target feature: \"%.*s\", enable it by setting a different -microarch or explicitly adding it through -target-features\n", LIT(disabled));
+			gb_exit(1);
+		}
+	}
+
 	if (build_context.show_debug_messages) {
 		debugf("Selected microarch: %.*s\n", LIT(march));
 		debugf("Default microarch features: %.*s\n", LIT(default_features));