Automatically add subfolders with a Jamfile in 3rdparty.

This allows hooking your own projects locally without having to touch this file, and have to resolve conflicts on svn up.
One still must configure --enable-3rdparty of course or add this to UserBuildConfig:
HAIKU_INCLUDE_3RDPARTY = 1 ;


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25455 a95241bf-73f2-0310-859d-f6bbb57e9c96

3rdparty/Jamfile

@@ -1,3 +1,10 @@
 SubDir HAIKU_TOP 3rdparty ;
 
-SubInclude HAIKU_TOP 3rdparty mmu_man ;
+# automatically pick any subdir that contains a Jamfile
+# this should allow hooking projects locally
+# without having to touch this file and get conflicts when it is updated.
+for subdir in [ GLOB $(SUBDIR) : [^.]* ] {
+	if [ GLOB $(subdir:G=) : Jamfile ] {
+		SubInclude HAIKU_TOP 3rdparty $(subdir:D=) ;
+	}
+}