[mac] Fix ftexport.sym target in Jamfile.

* Jamfile: Update the directories of the header files scanned for
ftexport.sym.  They were incorrect since the migration of the
header files, on 2015-06-22.  Either inexisting include/cache
(removed on 2006-03-20) is not needed to be listed explicitly.
Now ftmac.h is scanned only in the case of Mac OS & Mac OS X.

ChangeLog

@@ -1,3 +1,13 @@
+2016-07-09  suzuki toshiya  <mpsuzuki@hiroshima-u.ac.jp>
+
+	[mac] Fix ftexport.sym target in Jamfile.
+
+	* Jamfile: Update the directories of the header files scanned for
+	ftexport.sym.  They were incorrect since the migration of the
+	header files, on 2015-06-22.  Either inexisting include/cache
+	(removed on 2006-03-20) is not needed to be listed explicitly.
+	Now ftmac.h is scanned only in the case of Mac OS & Mac OS X.
+
 2016-07-08  Alexei Podtelezhnikov  <apodtele@gmail.com>
 
 	[smooth] Sub-banding protocol revision.

Jamfile

@@ -161,7 +161,20 @@ SubInclude FT2_TOP $(FT2_SRC_DIR) tools ;
 rule GenExportSymbols
 {
   local  apinames = apinames$(SUFEXE) ;
-  local  headers  = [ Glob $(2) : *.h ] ;
+  local  aheader ;
+  local  headers ;
+
+  for aheader in [ Glob $(2) : *.h ]
+  {
+    switch $(aheader)
+    {
+      case */ftmac.h :
+        if ( $(MAC) || $(OS) = MACOSX ) {
+          headers += $(aheader) ;
+        }
+      case *.h : headers += $(aheader) ;
+    }
+  }
 
   LOCATE on $(1) = $(ALL_LOCATE_TARGET) ;
 
@@ -177,7 +190,7 @@ actions GenExportSymbols1 bind APINAMES
   $(APINAMES) $(2) > $(1)
 }
 
-GenExportSymbols  ftexport.sym : include include/cache ;
+GenExportSymbols  ftexport.sym : include/freetype ;
 
 # Test files (hinter debugging).  Only used by FreeType developers.
 #