Tweak another PATH_MAX for hurd

debian/patches/hurd-pathmax.diff

@@ -41,3 +41,19 @@ Index: llvm-toolchain-snapshot_3.5~svn211597/lib/Support/Unix/Path.inc
  #endif
  
  using namespace llvm;
+Index: llvm-toolchain-snapshot-3.8~svn245286/tools/dsymutil/DwarfLinker.cpp
+===================================================================
+--- llvm-toolchain-snapshot-3.8~svn245286.orig/tools/dsymutil/DwarfLinker.cpp
++++ llvm-toolchain-snapshot-3.8~svn245286/tools/dsymutil/DwarfLinker.cpp
+@@ -1450,6 +1450,11 @@ private:
+   uint32_t LastCIEOffset;
+ };
+
++// For GNU Hurd
++#if defined(__GNU__) && !defined(PATH_MAX)
++# define PATH_MAX 4096
++#endif
++
+ /// \brief Similar to DWARFUnitSection::getUnitForOffset(), but
+ /// returning our CompileUnit object instead.
+ CompileUnit *DwarfLinker::getUnitForOffset(unsigned Offset) {