From 1ea34ed10cafc953fc7d2c08c0fb630af4fb002e Mon Sep 17 00:00:00 2001
From: Ron Economos <w6rz@comcast.net>
Date: Tue, 8 Dec 2020 01:57:11 -0800
Subject: [PATCH] cmake: Detect if cpu_features submodule is present.

---
 CMakeLists.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f90523053..c5356a86d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -122,6 +122,9 @@ else()
   option(VOLK_CPU_FEATURES "Volk uses cpu_features" OFF)
 endif()
 if (VOLK_CPU_FEATURES)
+  if(NOT EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/cpu_features/CMakeLists.txt" )
+    message(FATAL_ERROR "cpu_features/CMakeLists.txt not found. Did you forget to git clone recursively?\nFix with: git submodule update --init")
+  endif()
   message(STATUS "Building Volk with cpu_features")
   set(BUILD_PIC ON CACHE BOOL
     "Build cpu_features with Position Independent Code (PIC)."