CMake: Fix linking pthread of CMake < 3.1

As reported in #1624, Ubuntu 14.04 LTS still uses CMake 2.8.12 which does not support the Threads::Threads target (added in CMake 3.1). This could be reverted once the required CMake version is bumped to 3.1+.

CMake: Fix linking pthread of CMake < 3.1
f0e911c8 · Rémi Verschelde · 1a19598e · f0e911c8
Commit f0e911c8 authored Dec 18, 2018 by Rémi Verschelde
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Showing with 13 additions and 3 deletions

CMakeLists.txt glslang/OSDependent/Unix/CMakeLists.txt +13 -3

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--- a/glslang/OSDependent/Unix/CMakeLists.txt
+++ b/glslang/OSDependent/Unix/CMakeLists.txt
@@ -2,10 +2,20 @@ add_library(OSDependent STATIC ossource.cpp ../osinclude.h)
 set_property(TARGET OSDependent PROPERTY FOLDER glslang)
 set_property(TARGET OSDependent PROPERTY POSITION_INDEPENDENT_CODE ON)
+# Link pthread
 set(CMAKE_THREAD_PREFER_PTHREAD ON)
-set(THREADS_PREFER_PTHREAD_FLAG ON)
+if(${CMAKE_VERSION} VERSION_LESS "3.1.0")
-find_package(Threads)
+    # Needed as long as we support CMake 2.8 for Ubuntu 14.04,
-target_link_libraries(OSDependent Threads::Threads)
+    # which does not support the recommended Threads::Threads target.
+    # https://cmake.org/cmake/help/v2.8.12/cmake.html#module:FindThreads
+    find_package(Threads)
+    target_link_libraries(OSDependent ${CMAKE_THREAD_LIBS_INIT})
+else()
+    # This is the recommended way, so we use it for 3.1+.
+    set(THREADS_PREFER_PTHREAD_FLAG ON)
+    find_package(Threads)
+    target_link_libraries(OSDependent Threads::Threads)
+endif()
 if(ENABLE_GLSLANG_INSTALL)
    install(TARGETS OSDependent