fusion2 build: enable unsafe code & define symbol for fusion

Author: Timothy Edrick Burhan

fusion-v2/ProjectSettings/ProjectSettings.asset

@@ -707,7 +707,8 @@ PlayerSettings:
   webGLThreadsSupport: 0
   webGLDecompressionFallback: 0
   webGLPowerPreference: 2
-  scriptingDefineSymbols: {}
+  scriptingDefineSymbols:
+    Standalone: FUSION_WEAVER;FUSION2
   additionalCompilerArguments: {}
   platformArchitecture: {}
   scriptingBackend: {}
@@ -728,7 +729,7 @@ PlayerSettings:
     tvOS: 1
   incrementalIl2cppBuild: {}
   suppressCommonWarnings: 1
-  allowUnsafeCode: 0
+  allowUnsafeCode: 1
   useDeterministicCompilation: 1
   enableRoslynAnalyzers: 1
   selectedPlatform: 0