This patch allows the build process to use the provided dependencies instead
of adding their source as CMake sub-directories (in which case "make install"
would install googletest's and googlebenchmark's libraries and headers).

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c1cba55..627550f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -36,7 +36,7 @@ MACRO(PTHREADPOOL_TARGET_ENABLE_CXX11 target)
 ENDMACRO()
 
 # ---[ Download deps
-IF(NOT DEFINED FXDIV_SOURCE_DIR)
+IF(FALSE)
   MESSAGE(STATUS "Downloading FXdiv to ${CMAKE_BINARY_DIR}/FXdiv-source (define FXDIV_SOURCE_DIR to avoid it)")
   CONFIGURE_FILE(cmake/DownloadFXdiv.cmake "${CMAKE_BINARY_DIR}/FXdiv-download/CMakeLists.txt")
   EXECUTE_PROCESS(COMMAND "${CMAKE_COMMAND}" -G "${CMAKE_GENERATOR}" .
@@ -46,7 +46,7 @@ IF(NOT DEFINED FXDIV_SOURCE_DIR)
   SET(FXDIV_SOURCE_DIR "${CMAKE_BINARY_DIR}/FXdiv-source" CACHE STRING "FXdiv source directory")
 ENDIF()
 
-IF(PTHREADPOOL_BUILD_TESTS AND NOT DEFINED GOOGLETEST_SOURCE_DIR)
+IF(FALSE)
   MESSAGE(STATUS "Downloading Google Test to ${CMAKE_BINARY_DIR}/googletest-source (define GOOGLETEST_SOURCE_DIR to avoid it)")
   CONFIGURE_FILE(cmake/DownloadGoogleTest.cmake "${CMAKE_BINARY_DIR}/googletest-download/CMakeLists.txt")
   EXECUTE_PROCESS(COMMAND "${CMAKE_COMMAND}" -G "${CMAKE_GENERATOR}" .
@@ -56,7 +56,7 @@ IF(PTHREADPOOL_BUILD_TESTS AND NOT DEFINED GOOGLETEST_SOURCE_DIR)
   SET(GOOGLETEST_SOURCE_DIR "${CMAKE_BINARY_DIR}/googletest-source" CACHE STRING "Google Test source directory")
 ENDIF()
 
-IF(PTHREADPOOL_BUILD_BENCHMARKS AND NOT DEFINED GOOGLEBENCHMARK_SOURCE_DIR)
+IF(FALSE)
   MESSAGE(STATUS "Downloading Google Benchmark to ${CMAKE_BINARY_DIR}/googlebenchmark-source (define GOOGLEBENCHMARK_SOURCE_DIR to avoid it)")
   CONFIGURE_FILE(cmake/DownloadGoogleBenchmark.cmake "${CMAKE_BINARY_DIR}/googlebenchmark-download/CMakeLists.txt")
   EXECUTE_PROCESS(COMMAND "${CMAKE_COMMAND}" -G "${CMAKE_GENERATOR}" .
@@ -150,27 +150,18 @@ IF(CMAKE_SYSTEM_NAME STREQUAL "Linux")
 ENDIF()
 
 # ---[ Configure FXdiv
-IF(NOT TARGET fxdiv)
+IF(FALSE)
   SET(FXDIV_BUILD_TESTS OFF CACHE BOOL "")
   SET(FXDIV_BUILD_BENCHMARKS OFF CACHE BOOL "")
   ADD_SUBDIRECTORY(
     "${FXDIV_SOURCE_DIR}"
     "${CMAKE_BINARY_DIR}/FXdiv")
 ENDIF()
-TARGET_LINK_LIBRARIES(pthreadpool PRIVATE fxdiv)
-
 INSTALL(TARGETS pthreadpool
   LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
   ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
 
 IF(PTHREADPOOL_BUILD_TESTS)
-  # ---[ Build google test
-  IF(NOT TARGET gtest)
-    SET(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
-    ADD_SUBDIRECTORY(
-      "${GOOGLETEST_SOURCE_DIR}"
-      "${CMAKE_BINARY_DIR}/googletest")
-  ENDIF()
 
   ADD_EXECUTABLE(pthreadpool-test test/pthreadpool.cc)
   SET_TARGET_PROPERTIES(pthreadpool-test PROPERTIES
@@ -188,14 +179,6 @@ IF(PTHREADPOOL_BUILD_TESTS)
 ENDIF()
 
 IF(PTHREADPOOL_BUILD_BENCHMARKS)
-  # ---[ Build google benchmark
-  IF(NOT TARGET benchmark)
-    SET(BENCHMARK_ENABLE_TESTING OFF CACHE BOOL "")
-    ADD_SUBDIRECTORY(
-      "${GOOGLEBENCHMARK_SOURCE_DIR}"
-      "${CMAKE_BINARY_DIR}/googlebenchmark")
-  ENDIF()
-
   ADD_EXECUTABLE(latency-bench bench/latency.cc)
   SET_TARGET_PROPERTIES(latency-bench PROPERTIES
     CXX_STANDARD 11
pan title='2022-08-05 00:14:29 +0200'>2022-08-05</span></td><td><a href='/guix/commit/doc/htmlxref.cnf?id=f9a267c6d266355b48bd12288f4414eaf4db8b33'>doc: Fix Guix manual URLs in 'htmlxref.cnf'.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes a regression introduced in
868da34d54365023223a4ff7520043ba55ad64e8.

* doc/htmlxref.cnf (GUIX): Remove "/guix".
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-06-16 21:52:49 -0400'>2022-06-16</span></td><td><a href='/guix/commit/doc/htmlxref.cnf?id=ec7a75034421654d2ece2ba20033b44d345547f0'>doc: Remove obsolete comment from htmlxref.cnf.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is follow up to &lt;https://issues.guix.gnu.org/55290&gt;.

* doc/htmlxref.cnf (geiser): Delete obsolete comment.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2022-04-08 19:59:25 +0200'>2022-04-08</span></td><td><a href='/guix/commit/doc/htmlxref.cnf?id=868da34d54365023223a4ff7520043ba55ad64e8'>doc: Fix cookbook URLs in htmlxref.cnf.</a><span class='msg-avail'>...<span class='msg-tooltip'>Reported by Greg Hogan &lt;code@greghogan.com&gt;.

* doc/htmlxref.cnf (GUIX_ROOT): New variable.
(GUIX, GUIX_COOKBOOK): Adjust.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-10-04 16:36:58 +0200'>2021-10-04</span></td><td><a href='/guix/commit/doc/htmlxref.cnf?id=1267c2e9efdb6e324ce1c7b1fcef242f8208a61f'>doc: Update htmlxref.cnf.</a><span class='msg-avail'>...<span class='msg-tooltip'>Update and fix broken references to cuirass, git, and guix-cookbook.

* doc/htmlxref.cnf: Update from Texinfo.  Factorize Guix manuals.
(cuirass, git, guix-cookbook, guix-cookbook.de, guix-cookbook.fr): New
entries.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Sarah Morgensen</td></tr>
<tr><td><span title='2021-04-24 16:46:22 +0200'>2021-04-24</span></td><td><a href='/guix/commit/doc/htmlxref.cnf?id=1ebd086286c3825cfae31e75f8394986f1a18736'>doc: Fix cross-reference URL to translated manual.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/htmlxref.cnf: Fix translated manual URL.
</span></span></td><td>Julien Lepiller</td></tr>