From d9b4ca5381e885fb827c07bef64d3145e9989a65 Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Thu, 6 Jun 2019 15:20:42 +0200
Subject: [PATCH] Fix build when not file system library required

---
 CMakeLists.txt               | 1 -
 cmake/modules/3rdParty.cmake | 8 +++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3fda3a8..26deeaf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -157,7 +157,6 @@ else ()
 endif ()
 
 # configure required libraries for std::filestream
-message(STATUS "calling use_filesystem()")
 use_standard_filesystem()
 
 # configure forcing UTF-8 code page under Windows
diff --git a/cmake/modules/3rdParty.cmake b/cmake/modules/3rdParty.cmake
index ad5fbf6..ac767c5 100644
--- a/cmake/modules/3rdParty.cmake
+++ b/cmake/modules/3rdParty.cmake
@@ -285,9 +285,11 @@ function (use_standard_filesystem)
     set(REQUIRED_LIBRARY FAILED)
     set(INDEX 0)
     foreach (LIBRARY "" "stdc++fs" "c++fs")
-        set(CMAKE_REQUIRED_LIBRARIES ${DEFAULT_REQUIRED_LIBRARIES} -l${LIBRARY})
-        check_cxx_source_compiles("${TEST_PROGRAM}" COULD_COMPILE_${INDEX})
-        if (COULD_COMPILE_${INDEX})
+        if (NOT LIBRARY STREQUAL "")
+            set(CMAKE_REQUIRED_LIBRARIES ${DEFAULT_REQUIRED_LIBRARIES} -l${LIBRARY})
+        endif ()
+        check_cxx_source_compiles("${TEST_PROGRAM}" COULD_COMPILE_TEST_PROGRAM_${INDEX})
+        if (COULD_COMPILE_TEST_PROGRAM_${INDEX})
             set(REQUIRED_LIBRARY "${LIBRARY}")
             break()
         endif ()