minor backend update from GZDoom.

source/common/engine/renderstyle.h

@@ -55,7 +55,7 @@ enum ETexMode
 };
 
 // Legacy render styles
-enum ERenderStyle
+enum ERenderStyle : int
 {
 	STYLE_None,				// Do not draw
 	STYLE_Normal,			// Normal; just copy the image to the screen

source/common/textures/bitmap.h

@@ -108,7 +108,7 @@ class FBitmap
 
 	FBitmap(const FBitmap &other) = delete;	// disallow because in nearly all cases this creates an unwanted copy.
 
-	FBitmap(FBitmap &&other)
+	FBitmap(FBitmap &&other) noexcept
 	{
 		data = other.data;
 		Pitch = other.Pitch;
@@ -122,7 +122,7 @@ class FBitmap
 
 	FBitmap &operator=(const FBitmap &other) = delete;	// disallow because in nearly all cases this creates an unwanted copy. Use Copy instead.
 
-	FBitmap &operator=(FBitmap &&other)
+	FBitmap &operator=(FBitmap &&other) noexcept
 	{
 		if (data != nullptr && FreeBuffer) delete[] data;
 		data = other.data;

source/common/utility/zstring.cpp

@@ -217,7 +217,7 @@ FString &FString::operator = (const FString &other)
 	return *this;
 }
 
-FString &FString::operator = (FString &&other)
+FString &FString::operator = (FString &&other) noexcept
 {
 	assert (Chars != NULL);
 

source/common/utility/zstring.h

@@ -179,7 +179,7 @@ class FString
 	const char &operator[] (unsigned long long index) const { return Chars[index]; }
 
 	FString &operator = (const FString &other);
-	FString &operator = (FString &&other);
+	FString &operator = (FString &&other) noexcept;
 	FString &operator = (const char *copyStr);
 
 	FString operator + (const FString &tail) const;