llvmPackages_git.libcxxabi: Replace vendored patch with fetch

https://reviews.llvm.org/D132298 is now landed, so we can fetch the
commit instead.

pkgs/development/compilers/llvm/git/libcxxabi/default.nix

@@ -1,5 +1,5 @@
 { lib, stdenv, llvm_meta, cmake, python3
-, monorepoSrc, runCommand
+, monorepoSrc, runCommand, fetchpatch
 , cxx-headers, libunwind, version
 , enableShared ? !stdenv.hostPlatform.isStatic
 }:
@@ -39,7 +39,13 @@ stdenv.mkDerivation rec {
 
   patches = [
     ./gnu-install-dirs.patch
-    ./skip-other-project-tests.patch
+
+    # https://reviews.llvm.org/D132298, Allow building libcxxabi alone
+    (fetchpatch {
+      url = "https://github.com/llvm/llvm-project/commit/e6a0800532bb409f6d1c62f3698bdd6994a877dc.patch";
+      sha256 = "1xyjd56m4pfwq8p3xh6i8lhkk9kq15jaml7qbhxdf87z4jjkk63a";
+      stripLen = 1;
+    })
   ];
 
   postPatch = ''

pkgs/development/compilers/llvm/git/libcxxabi/skip-other-project-tests.patch

@@ -1,45 +0,0 @@
---- a/CMakeLists.txt
-+++ b/CMakeLists.txt
-@@ -131,10 +131,21 @@ if (NOT LIBCXXABI_ENABLE_SHARED AND NOT LIBCXXABI_ENABLE_STATIC)
-   message(FATAL_ERROR "libc++abi must be built as either a shared or static library.")
- endif()
-
--# TODO: Remove this, which shouldn't be necessary since we know we're being built
--#       side-by-side with libc++.
- set(LIBCXXABI_LIBCXX_INCLUDES "" CACHE PATH
-     "Specify path to libc++ includes.")
-+if (NOT libcxx IN_LIST LLVM_ENABLE_RUNTIMES)
-+  if (NOT IS_DIRECTORY ${LIBCXXABI_LIBCXX_INCLUDES})
-+    message(FATAL_ERROR
-+      "LIBCXXABI_LIBCXX_INCLUDES=${LIBCXXABI_LIBCXX_INCLUDES} is not a valid directory. "
-+      "Please provide the path to where the libc++ headers have been installed.")
-+  endif()
-+  add_library(cxx-headers INTERFACE)
-+  if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC" OR "${CMAKE_CXX_SIMULATE_ID}" STREQUAL "MSVC")
-+    target_compile_options(cxx-headers INTERFACE /I "${LIBCXXABI_LIBCXX_INCLUDES}")
-+  else()
-+    target_compile_options(cxx-headers INTERFACE -I "${LIBCXXABI_LIBCXX_INCLUDES}")
-+  endif()
-+endif()
-
- set(LIBCXXABI_HERMETIC_STATIC_LIBRARY_DEFAULT OFF)
- if (WIN32)
---- a/test/CMakeLists.txt
-+++ b/test/CMakeLists.txt
-@@ -61,9 +61,13 @@ if (LIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY)
-   list(APPEND LIBCXXABI_TEST_DEPS cxx_external_threads)
- endif()
-
--list(APPEND LIBCXXABI_TEST_DEPS cxx)
--if (LIBCXXABI_USE_LLVM_UNWINDER AND TARGET unwind)
--  list(APPEND LIBCXXABI_TEST_DEPS unwind)
-+if(libcxx IN_LIST LLVM_ENABLE_RUNTIMES)
-+  list(APPEND LIBCXXABI_TEST_DEPS cxx)
-+endif()
-+if(libunwind IN_LIST LLVM_ENABLE_RUNTIMES)
-+  if (LIBCXXABI_USE_LLVM_UNWINDER AND TARGET unwind)
-+    list(APPEND LIBCXXABI_TEST_DEPS unwind)
-+  endif()
- endif()
-
- set(AUTO_GEN_COMMENT "## Autogenerated by libcxxabi configuration.\n# Do not edit!")