dwrite: Avoid redefining the DWRITE_GLYPH_RUN typedef.

[Francois Gouget]

Doing so breaks compilation on non-C11 compilers.
---

Based on a patch by Henri Verbeet.

Note that the PSDK does not define any typedef in dwrite.h, yet does as 
if they were present. That seems to be a C++-only feature. This means we 
do have to define these typedefs so we can use the right prototypes in 
C.

Also the DWRITE_GLYPH_RUN typedef is the only one being defined in 
another header which is lucky otherwise we'd have to do a lot more of 
this.

This patch fixes compilation on FreeBSD and presumably on any platform 
that uses GCC < 4.6(*). Note that it's not just the old FreeBSD 7.0 and 
8.1. FreeBSD 10's brand new Clang compiler also complained about this 
but only as a warning (and there's a compiler option to disable that 
warning).

(*) https://gcc.gnu.org/wiki/C11Status
    However that page seems to imply that anonymous structs and unions 
    are not supported in GCC < 4.6 which is wrong.


 include/d2d1.idl   | 3 +++
 include/dwrite.idl | 8 ++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/include/d2d1.idl b/include/d2d1.idl
index 4934acc..1623e46 100644
--- a/include/d2d1.idl
+++ b/include/d2d1.idl
@@ -37,7 +37,10 @@ interface IDWriteTextLayout;
 interface IWICBitmapSource;
 interface IWICBitmap;
 
+cpp_quote("#ifndef __dwrite_h__")
+/* already defined in dwrite.h but needed for WIDL */
 typedef struct DWRITE_GLYPH_RUN DWRITE_GLYPH_RUN;
+cpp_quote("#endif /* __dwrite_h__ */")
 
 typedef D2D_POINT_2F D2D1_POINT_2F;
 typedef D2D_MATRIX_3X2_F D2D1_MATRIX_3X2_F;
diff --git a/include/dwrite.idl b/include/dwrite.idl
index 1888215..2ae5164 100644
--- a/include/dwrite.idl
+++ b/include/dwrite.idl
@@ -382,7 +382,11 @@ typedef struct DWRITE_TRIMMING
     UINT32 delimiterCount;
 } DWRITE_TRIMMING;
 
-typedef struct DWRITE_GLYPH_RUN
+cpp_quote("#ifndef __d2d1_h__")
+typedef struct DWRITE_GLYPH_RUN DWRITE_GLYPH_RUN;
+cpp_quote("#endif /* __d2d1_h__ */")
+
+struct DWRITE_GLYPH_RUN
 {
     IDWriteFontFace* fontFace;
     FLOAT fontEmSize;
@@ -392,7 +396,7 @@ typedef struct DWRITE_GLYPH_RUN
     DWRITE_GLYPH_OFFSET const* glyphOffsets;
     BOOL isSideways;
     UINT32 bidiLevel;
-} DWRITE_GLYPH_RUN;
+};
 
 typedef struct DWRITE_GLYPH_RUN_DESCRIPTION
 {
-- 
2.1.1