linuxPackages.bpftrace: 0.9 -> 0.9.1

Signed-off-by: Austin Seipp <aseipp@pobox.com>

pkgs/os-specific/linux/bpftrace/fix-kernel-include-dir.patch

@@ -8,11 +8,11 @@ Date:   Fri May 3 00:47:12 2019 -0500
 
 diff --git a/src/clang_parser.cpp b/src/clang_parser.cpp
 index b1db8ff..0cfb01f 100644
---- a/src/clang_parser.cpp
-+++ b/src/clang_parser.cpp
+--- a/src/utils.cpp
++++ b/src/utils.cpp
 @@ -140,6 +140,9 @@ static bool is_dir(const std::string& path)
  // Both ksrc and kobj are guaranteed to be != "", if at least some trace of kernel sources was found.
- static std::tuple<std::string, std::string> get_kernel_dirs(const struct utsname& utsname)
+ std::tuple<std::string, std::string> get_kernel_dirs(const struct utsname& utsname)
  {
 +  // NB (aseipp): special case the kernel directory for nix
 +  return { "@NIX_KERNEL_SRC@/source", "@NIX_KERNEL_SRC@/build" };