[build] Fix multi and C++ builds.

The following builds were failing due to previous changes:

  make multi
  make multi CC="c++"

* include/freetype/config/ftconfig.h: Remove `FT_END_HEADER'.

* include/freetype/config/ftheader.h (FT_BEGIN_HEADER,
FT_END_HEADER): Protect against redefinition.

* src/cache/ftccache.h, src/cache/ftcmru.h, src/pcf/pcfutil.h,
src/psaux/pserror.h, src/psaux/psft.h, src/psaux/psstack.h,
src/sfnt/woff2tags.h: Include `compiler-macros.h'.

* src/sfnt/woff2tags.c: Include `woff2tags.h'.

ChangeLog

@@ -1,3 +1,23 @@
+2020-07-06  David Turner  <david@freetype.org>
+
+	[build] Fix multi and C++ builds.
+
+	The following builds were failing due to previous changes:
+
+	  make multi
+	  make multi CC="c++"
+
+	* include/freetype/config/ftconfig.h: Remove `FT_END_HEADER'.
+
+	* include/freetype/config/ftheader.h (FT_BEGIN_HEADER,
+	FT_END_HEADER): Protect against redefinition.
+
+	* src/cache/ftccache.h, src/cache/ftcmru.h, src/pcf/pcfutil.h,
+	src/psaux/pserror.h, src/psaux/psft.h, src/psaux/psstack.h,
+	src/sfnt/woff2tags.h: Include `compiler-macros.h'.
+
+	* src/sfnt/woff2tags.c: Include `woff2tags.h'.
+
 2020-07-06  Werner Lemberg  <wl@gnu.org>
 
 	[psaux] Improve `t1_decoder_parse_metrics' (#58646).

include/freetype/config/ftconfig.h

@@ -45,9 +45,6 @@
 #include <freetype/config/public-macros.h>
 #include <freetype/config/mac-support.h>
 
-FT_END_HEADER
-
-
 #endif /* FTCONFIG_H_ */
 
 

include/freetype/config/ftheader.h

@@ -30,10 +30,12 @@
   /*    encapsulated in an `extern "C" { .. }` block when included from a  */
   /*    C++ compiler.                                                      */
   /*                                                                       */
-#ifdef __cplusplus
-#define FT_BEGIN_HEADER  extern "C" {
-#else
-#define FT_BEGIN_HEADER  /* nothing */
+#ifndef FT_BEGIN_HEADER
+#  ifdef __cplusplus
+#    define FT_BEGIN_HEADER  extern "C" {
+#  else
+#  define FT_BEGIN_HEADER  /* nothing */
+#  endif
 #endif
 
 
@@ -48,10 +50,12 @@
   /*    encapsulated in an `extern "C" { .. }` block when included from a  */
   /*    C++ compiler.                                                      */
   /*                                                                       */
-#ifdef __cplusplus
-#define FT_END_HEADER  }
-#else
-#define FT_END_HEADER  /* nothing */
+#ifndef FT_END_HEADER
+#  ifdef __cplusplus
+#    define FT_END_HEADER  }
+#  else
+#   define FT_END_HEADER  /* nothing */
+#  endif
 #endif
 
 

src/cache/ftccache.h

@@ -19,7 +19,7 @@
 #ifndef FTCCACHE_H_
 #define FTCCACHE_H_
 
-
+#include <freetype/internal/compiler-macros.h>
 #include "ftcmru.h"
 
 FT_BEGIN_HEADER

src/cache/ftcmru.h

@@ -45,6 +45,7 @@
 
 
 #include <freetype/freetype.h>
+#include <freetype/internal/compiler-macros.h>
 
 #ifdef FREETYPE_H
 #error "freetype.h of FreeType 1 has been loaded!"

src/pcf/pcfutil.h

@@ -31,7 +31,7 @@ THE SOFTWARE.
 
 #include <ft2build.h>
 #include FT_CONFIG_CONFIG_H
-
+#include <freetype/internal/compiler-macros.h>
 
 FT_BEGIN_HEADER
 

src/psaux/pserror.h

@@ -50,6 +50,7 @@
 
 
 #include <freetype/fterrors.h>
+#include <freetype/internal/compiler-macros.h>
 #include "psft.h"
 
 

src/psaux/psft.h

@@ -40,9 +40,9 @@
 #define PSFT_H_
 
 
+#include <freetype/internal/compiler-macros.h>
 #include "pstypes.h"
 
-
   /* TODO: disable asserts for now */
 #define CF2_NDEBUG
 

src/psaux/psstack.h

@@ -39,6 +39,7 @@
 #ifndef PSSTACK_H_
 #define PSSTACK_H_
 
+#include <freetype/internal/compiler-macros.h>
 
 FT_BEGIN_HEADER
 

src/sfnt/woff2tags.c

@@ -17,7 +17,7 @@
 
 
 #include <freetype/tttags.h>
-
+#include "woff2tags.h"
 
   /*
    * Return tag from index in the order given in WOFF2 specification.

src/sfnt/woff2tags.h

@@ -21,6 +21,7 @@
 
 
 #include <freetype/internal/ftobjs.h>
+#include <freetype/internal/compiler-macros.h>
 
 
 FT_BEGIN_HEADER