[build] Fixed Linux build with STDCXX SYNC enabled

.github/workflows/cxx11-macos.yaml

@@ -0,0 +1,23 @@
+name: cxx11_win
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    name: macos-cxx11
+    runs-on: macos-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: configure
+      run: |
+        mkdir _build && cd _build
+        cmake ../ -DENABLE_STDCXX_SYNC=ON -DENABLE_ENCRYPTION=OFF -DENABLE_UNITTESTS=ON
+    - name: build
+      run: cd _build && cmake --build ./
+    - name: test
+      run: cd _build && ctest --extra-verbose

.github/workflows/cxx11-ubuntu.yaml

@@ -0,0 +1,23 @@
+name: cxx11_win
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    name: ubuntu-cxx11
+    runs-on: ubuntu-18.04
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: configure
+      run: |
+        mkdir _build && cd _build
+        cmake ../ -DENABLE_STDCXX_SYNC=ON -DENABLE_UNITTESTS=ON
+    - name: build
+      run: cd _build && cmake --build ./
+    - name: test
+      run: cd _build && ctest --extra-verbose

.github/workflows/cxx11-win.yaml

@@ -9,6 +9,7 @@ on:
 jobs:
   build:
 
+    name: windows-cxx11
     runs-on: windows-latest
 
     steps:

CMakeLists.txt

@@ -351,13 +351,13 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "GNU|Intel|Clang|AppleClang")
 	# At the bottom there's information about C++98, which is default up to 6.1 version.
 	# For all other compilers - including Clang - we state that the default C++ standard is AT LEAST 11.
 	if (${CMAKE_CXX_COMPILER_ID} STREQUAL GNU AND ${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 6.1)
-	    message(STATUS "NOTE: GCC ${CMAKE_CXX_COMPILER_VERSION} is detected with default C++98. Forcing C++11 on applications.")
+		message(STATUS "NOTE: GCC ${CMAKE_CXX_COMPILER_VERSION} is detected with default C++98. Forcing C++11 on applications.")
 		set (FORCE_CXX_STANDARD 1)
 	elseif (${CMAKE_CXX_COMPILER_ID} MATCHES "Clang|AppleClang")
 		message(STATUS "NOTE: CLANG ${CMAKE_CXX_COMPILER_VERSION} detected, unsure if >=C++11 is default, forcing C++11 on applications")
 		set (FORCE_CXX_STANDARD 1)
 	else() 
-	    message(STATUS "NOTE: ${CMAKE_CXX_COMPILER_ID} ${CMAKE_CXX_COMPILER_VERSION} - assuming default C++11.")
+		message(STATUS "NOTE: ${CMAKE_CXX_COMPILER_ID} ${CMAKE_CXX_COMPILER_VERSION} - assuming default C++11.")
 	endif()
 else()
 	message(STATUS "COMPILER: ${CMAKE_CXX_COMPILER_ID} (${CMAKE_CXX_COMPILER}) - NOT GNU compat")
@@ -629,7 +629,8 @@ if (ENABLE_CODE_COVERAGE)
 	endif()
 endif()
 
-if (ENABLE_STDCXX_SYNC)
+# On Linux pthreads have to be linked even when using C++11 threads
+if (ENABLE_STDCXX_SYNC AND NOT LINUX)
 	message(STATUS "Pthread library: C++11")
 elseif (PTHREAD_LIBRARY AND PTHREAD_INCLUDE_DIR)
 	message(STATUS "Pthread library: ${PTHREAD_LIBRARY}")