gdiplus: Make get_font_hfont() static.

dlls/gdiplus/gdiplus_private.h

@@ -63,8 +63,6 @@ extern void calc_curve_bezier_endp(REAL xend, REAL yend, REAL xadj, REAL yadj,
 
 extern void free_installed_fonts(void) DECLSPEC_HIDDEN;
 
-extern void get_font_hfont(GpGraphics *graphics, GDIPCONST GpFont *font, HFONT *hfont) DECLSPEC_HIDDEN;
-
 extern BOOL lengthen_path(GpPath *path, INT len) DECLSPEC_HIDDEN;
 
 extern GpStatus trace_path(GpGraphics *graphics, GpPath *path) DECLSPEC_HIDDEN;

dlls/gdiplus/graphics.c

@@ -2113,7 +2113,7 @@ end:
     return stat;
 }
 
-void get_font_hfont(GpGraphics *graphics, GDIPCONST GpFont *font, HFONT *hfont)
+static void get_font_hfont(GpGraphics *graphics, GDIPCONST GpFont *font, HFONT *hfont)
 {
     HDC hdc = CreateCompatibleDC(0);
     GpPointF pt[3];