clang-11 needs explicit cast

https://bugs.gentoo.org/739284
--- a/BPGame.cpp
+++ b/BPGame.cpp
@@ -1507,7 +1507,7 @@ int BPGame::DivRem(int Num, int Div, int* Rem) {
 }
 
 void BPGame::DrawLine(int fromx, int fromy, int tox, int toy, Colour* col, float width) {	
-	GLfloat vertices[] = { fromx, fromy, tox, toy }; 
+	GLfloat vertices[] = { (GLfloat)fromx, (GLfloat)fromy, (GLfloat)tox, (GLfloat)toy }; 
 
 	glDisable(GL_TEXTURE_2D);
 	glLineWidth(width);