sci-libs/vtk: fix build with >=media-libs/freetype-2.10.3

Closes: https://bugs.gentoo.org/751088
Package-Manager: Portage-3.0.8, Repoman-3.0.2
Signed-off-by: Sam James <sam@gentoo.org>

sci-libs/vtk/files/vtk-8.2.0-freetype-2.10.3-provide-FT_CALLBACK_DEF.patch

@@ -0,0 +1,18 @@
+--- VTK-8.2.0/ThirdParty/freetype/vtk_freetype.h.in.orig	2019-01-30 18:15:13.000000000 +0100
++++ VTK-8.2.0/ThirdParty/freetype/vtk_freetype.h.in	2020-10-17 00:03:32.730820908 +0200
+@@ -20,6 +20,15 @@
+ 
+ #ifdef VTK_USE_SYSTEM_FREETYPE
+ # include <ft2build.h>
++/* FT_CALLBACK_DEF no longer exported since freetype-2.10.3 */
++/* has been moved to <freetype/internal/compiler-macros.h> */
++# ifndef FT_CALLBACK_DEF
++#  ifdef __cplusplus
++#   define FT_CALLBACK_DEF( x )  extern "C"  x
++#  else
++#   define FT_CALLBACK_DEF( x )  static  x
++#  endif
++# endif /* FT_CALLBACK_DEF */
+ #else
+ # include <vtkfreetype/include/ft2build.h>
+ #endif

sci-libs/vtk/vtk-8.2.0.ebuild

@@ -129,6 +129,7 @@ PATCHES=(
 	"${FILESDIR}"/${P}-gcc-10.patch # bug 723374
 	"${FILESDIR}"/${P}-fno-common.patch # bug 721048
 	"${FILESDIR}"/${P}-py38.patch
+	"${FILESDIR}"/${P}-freetype-2.10.3-provide-FT_CALLBACK_DEF.patch # bug #751088
 )
 
 RESTRICT="test"