cocoa_gl_ctx: cast contentView to NSView* for -bounds on 32-bit

Fullscreen enter on the non-Metal path failed to compile on 32-bit
Darwin (10.5 PPC, 10.6 i386):

  cocoa_gl_ctx.m:535: error: incompatible type for argument 1 of
  'setFrame:'

-[NSWindow contentView] returns id on the 10.5-10.9 SDKs (only
tightened to NSView* in 10.10).  When the receiver type is id, GCC
resolves selectors against every matching @interface it's seen.
-bounds is declared on two unrelated classes in our translation unit:

  -[NSView  bounds] returns NSRect
  -[CALayer bounds] returns CGRect

On 64-bit macOS NSRect is a typedef for CGRect and the distinction
is invisible, but on 32-bit Darwin they're separate incompatible
structs (different CGFloat / NSPoint / NSSize underneath).  GCC
resolves -bounds to CALayer's CGRect-returning method, and then
-setFrame:'s NSRect parameter won't accept the CGRect rvalue.

Cast the receiver to NSView* so -bounds resolves to NSView's NSRect
version.  Same fix class as 8e428f4 (ui_cocoa.m:629,726) and
47a7fd4.

Not needed at the -addSubview: call sites (534, 554) because
-addSubview: is unique to NSView - no resolution ambiguity there.

Author: LibretroAdmin

gfx/drivers_context/cocoa_gl_ctx.m

@@ -532,7 +532,14 @@ static bool cocoa_gl_gfx_ctx_set_video_mode(void *data,
          [g_view retain];
          [g_view removeFromSuperviewWithoutNeedingDisplay];
          [[fullscreen_window contentView] addSubview:g_view];
-         [g_view setFrame:[[fullscreen_window contentView] bounds]];
+         /* -[NSWindow contentView] returns id on the 10.5-10.9 SDKs,
+          * which means GCC can resolve -bounds either to -[NSView
+          * bounds] (NSRect) or -[CALayer bounds] (CGRect).  On 32-bit
+          * Darwin those are distinct incompatible structs, so the
+          * implicit CGRect -> NSRect (setFrame:'s parameter) coercion
+          * fails to compile.  Cast the receiver to NSView* so the
+          * right -bounds wins.  Same fix class as 8e428f4e67. */
+         [g_view setFrame:[(NSView*)[fullscreen_window contentView] bounds]];
          [g_view release];
 
          /* Order the windowed window out, bring the fullscreen window