Add flag `FT_CONFIG_OPTION_SVG`.

This flag is going to be used to conditionally compile support for OT-SVG
glyphs.  FreeType will do the parsing and rely on external hooks for
rendering of OT-SVG glyphs.

* devel/ftoption.h, include/freetype/config/ftoption.h
(FT_CONFIG_OPTION_SVG): New flag.
diff --git a/devel/ftoption.h b/devel/ftoption.h
index 0560fca..b2363d7 100644
--- a/devel/ftoption.h
+++ b/devel/ftoption.h
@@ -527,6 +527,20 @@
 
   /**************************************************************************
    *
+   * OpenType SVG Glyph Support
+   *
+   *   Setting this macro enables support for OpenType SVG glyphs.  By
+   *   default, FreeType can only fetch SVG documents.  However, it can also
+   *   render them if external rendering hook functions are plugged in at
+   *   runtime.
+   *
+   *   More details on the hooks can be found in file `otsvg.h`.
+   */
+#define FT_CONFIG_OPTION_SVG
+
+
+  /**************************************************************************
+   *
    * Error Strings
    *
    *   If this macro is set, `FT_Error_String` will return meaningful
@@ -1004,8 +1018,8 @@
 #error "Invalid CFF darkening parameters!"
 #endif
 
-FT_END_HEADER
 
+FT_END_HEADER
 
 #endif /* FTOPTION_H_ */
 
diff --git a/include/freetype/config/ftoption.h b/include/freetype/config/ftoption.h
index ea1c9b6..c5bde24 100644
--- a/include/freetype/config/ftoption.h
+++ b/include/freetype/config/ftoption.h
@@ -529,6 +529,20 @@
 
   /**************************************************************************
    *
+   * OpenType SVG Glyph Support
+   *
+   *   Setting this macro enables support for OpenType SVG glyphs.  By
+   *   default, FreeType can only fetch SVG documents.  However, it can also
+   *   render them if external rendering hook functions are plugged in at
+   *   runtime.
+   *
+   *   More details on the hooks can be found in file `otsvg.h`.
+   */
+#define FT_CONFIG_OPTION_SVG
+
+
+  /**************************************************************************
+   *
    * Error Strings
    *
    *   If this macro is set, `FT_Error_String` will return meaningful
@@ -1006,8 +1020,8 @@
 #error "Invalid CFF darkening parameters!"
 #endif
 
-FT_END_HEADER
 
+FT_END_HEADER
 
 #endif /* FTOPTION_H_ */