commit 01a20aa: [Minor] Add autodetection of the libc++

[Vsevolod Stakhov]

Author: Vsevolod Stakhov
Date: 2023-02-19 19:34:34 +0000
URL: https://github.com/rspamd/rspamd/commit/01a20aa2ed551d0c8ae275caccb3046841aad62b (HEAD -> master)

[Minor] Add autodetection of the libc++

---
 cmake/Toolset.cmake | 17 ++++++++++++++++-
 debian/rules        |  2 +-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/cmake/Toolset.cmake b/cmake/Toolset.cmake
index cd372af13..fc019cf35 100644
--- a/cmake/Toolset.cmake
+++ b/cmake/Toolset.cmake
@@ -48,9 +48,24 @@ elseif (COMPILER_CLANG)
     SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-unused-command-line-argument")
     SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-ignored-optimization-argument")
     SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-ignored-optimization-argument")
+    if (ENABLE_LIBCXX MATCHES "AUTO")
+        include(CheckCXXSourceCompiles)
+        set(OLD_CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
+        check_cxx_source_compiles("
+#include <version>
+int main() { return 0; }
+        " HAVE_LIBCXX )
+        if (HAVE_LIBCXX)
+            SET(ENABLE_LIBCXX "ON")
+        else()
+            SET(ENABLE_LIBCXX "OFF")
+        endif()
+        set(CMAKE_CXX_FLAGS "${OLD_CMAKE_CXX_FLAGS}")
+    endif()
     if (ENABLE_LIBCXX MATCHES "ON")
-        # Use libc++ as libstdc++ is buggy in many cases
         set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
+        set(CLANG_DEFAULT_CXX_STDLIB "libc++")
     endif ()
 else ()
     message (WARNING "You are using an unsupported compiler ${CMAKE_C_COMPILER_ID}. Compilation has only been tested with Clang 4+ and GCC 4+.")
diff --git a/debian/rules b/debian/rules
index d12924d22..72823c3fc 100755
--- a/debian/rules
+++ b/debian/rules
@@ -54,7 +54,7 @@ configure_%:
 		-DENABLE_LIBUNWIND=ON \
 		-DWANT_SYSTEMD_UNITS=ON \
 		-DENABLE_STATIC_LIBCXX=OFF \
-		-DENABLE_LIBCXX=OFF \
+		-DENABLE_LIBCXX=AUTO \
 		$(ENABLE_HYPERSCAN) \
 		$(ENABLE_LUAJIT) \
 		$(ENABLE_JEMALLOC) \