Non libX11 build fix

Reverted the portion of the following cl which broke the build:
https://swiftshader-review.googlesource.com/c/SwiftShader/+/15909

Change-Id: I4a0e7ef5507dd5502861ccf34c400f1feb54b0cc
Reviewed-on: https://swiftshader-review.googlesource.com/20228
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
diff --git a/src/OpenGL/libEGL/libEGL.cpp b/src/OpenGL/libEGL/libEGL.cpp
index fa8a529..b2ef237 100644
--- a/src/OpenGL/libEGL/libEGL.cpp
+++ b/src/OpenGL/libEGL/libEGL.cpp
@@ -1248,14 +1248,30 @@
 	#if defined(__linux__) && !defined(__ANDROID__)
 		switch(platform)
 		{
-		case EGL_PLATFORM_X11_EXT:
-		case EGL_PLATFORM_GBM_KHR:
-			break;
+		#if defined(USE_X11)
+		case EGL_PLATFORM_X11_EXT: break;
+		#endif
+		case EGL_PLATFORM_GBM_KHR: break;
 		default:
 			return error(EGL_BAD_PARAMETER, EGL_NO_DISPLAY);
 		}
 
-		if(platform == EGL_PLATFORM_X11_EXT)
+		if(platform == EGL_PLATFORM_GBM_KHR)
+		{
+			if(native_display != (void*)EGL_DEFAULT_DISPLAY)
+			{
+				return error(EGL_BAD_PARAMETER, EGL_NO_DISPLAY);   // Unimplemented
+			}
+
+			if(attrib_list && attrib_list[0] != EGL_NONE)
+			{
+				return error(EGL_BAD_ATTRIBUTE, EGL_NO_DISPLAY);   // Unimplemented
+			}
+
+			return success(HEADLESS_DISPLAY);
+		}
+		#if defined(USE_X11)
+		else if(platform == EGL_PLATFORM_X11_EXT)
 		{
 			if(!libX11)
 			{
@@ -1272,20 +1288,7 @@
 				return error(EGL_BAD_ATTRIBUTE, EGL_NO_DISPLAY);   // Unimplemented
 			}
 		}
-		else if(platform == EGL_PLATFORM_GBM_KHR)
-		{
-			if(native_display != (void*)EGL_DEFAULT_DISPLAY)
-			{
-				return error(EGL_BAD_PARAMETER, EGL_NO_DISPLAY);   // Unimplemented
-			}
-
-			if(attrib_list && attrib_list[0] != EGL_NONE)
-			{
-				return error(EGL_BAD_ATTRIBUTE, EGL_NO_DISPLAY);   // Unimplemented
-			}
-
-			return success(HEADLESS_DISPLAY);
-		}
+		#endif
 
 		return success(PRIMARY_DISPLAY);   // We only support the default display
 	#else