add patch to separate build of libfaiss_avx2 from libfaiss

recipe/meta.yaml

@@ -77,6 +77,8 @@ source:
     - patches/0001-use-c-14.patch  # [win and cuda_compiler_version != "10.2"]
     # patch for avoiding crash in GPU test suite on windows
     - patches/0002-skip-test_stress-for-GPU-on-windows.patch
+    # enable building libfaiss_avx2 without libfaiss
+    - patches/0003-enable-building-libfaiss_avx2-without-libfaiss.patch
 
 build:
   number: 0

recipe/patches/0001-use-c-14.patch

@@ -1,7 +1,7 @@
 From a2e1ffdca0490b4e377c9aebb5ab5b554669c5fb Mon Sep 17 00:00:00 2001
 From: "H. Vetinari" <h.vetinari@gmx.com>
 Date: Mon, 26 Oct 2020 22:44:44 +0100
-Subject: [PATCH 1/2] use c++14
+Subject: [PATCH 1/3] use c++14
 
 ---
  CMakeLists.txt              | 2 +-

recipe/patches/0002-skip-test_stress-for-GPU-on-windows.patch

@@ -1,7 +1,7 @@
 From baa69fd2dec67313670eb271dff4717e25bd51f7 Mon Sep 17 00:00:00 2001
 From: "H. Vetinari" <h.vetinari@gmx.com>
 Date: Fri, 19 Feb 2021 14:14:31 +0100
-Subject: [PATCH 2/2] skip test_stress for GPU on windows
+Subject: [PATCH 2/3] skip test_stress for GPU on windows
 
 ---
  faiss/gpu/test/test_gpu_basics.py | 2 ++

recipe/patches/0003-enable-building-libfaiss_avx2-without-libfaiss.patch

@@ -0,0 +1,46 @@
+From c6396047a9f44ee4349bea3da1e903b9019d3d1a Mon Sep 17 00:00:00 2001
+From: "H. Vetinari" <h.vetinari@gmx.com>
+Date: Wed, 2 Jun 2021 22:58:19 +0200
+Subject: [PATCH 3/3] enable building libfaiss_avx2 without libfaiss
+
+---
+ faiss/CMakeLists.txt | 19 +++++++++++--------
+ 1 file changed, 11 insertions(+), 8 deletions(-)
+
+diff --git a/faiss/CMakeLists.txt b/faiss/CMakeLists.txt
+index 30d573f0..4231ae9b 100644
+--- a/faiss/CMakeLists.txt
++++ b/faiss/CMakeLists.txt
+@@ -225,18 +225,21 @@ else()
+   target_link_libraries(faiss_avx2 PRIVATE ${LAPACK_LIBRARIES})
+ endif()
+
+-install(TARGETS faiss
+-  EXPORT faiss-targets
+-  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+-  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+-  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+-  INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+-)
+-if(FAISS_OPT_LEVEL STREQUAL "avx2")
++if(NOT FAISS_OPT_LEVEL STREQUAL "avx2")
++  install(TARGETS faiss
++    EXPORT faiss-targets
++    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
++    ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
++    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
++    INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
++  )
++else()
+   install(TARGETS faiss_avx2
+     EXPORT faiss-targets
++    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+     ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+     LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
++    INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+   )
+ endif()
+
+-- 
+2.31.1.windows.1
+