From: Daniel Arndt <arndtd@ornl.gov>
Date: Fri, 30 Jun 2023 20:29:48 +0000 (-0400)
Subject: Use -Werror again in enable_if_supported
X-Git-Tag: relicensing~823^2~2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7699f518e5f17f07f5fefe033a7322f80f901a41;p=dealii.git

Use -Werror again in enable_if_supported
---

diff --git a/cmake/macros/macro_enable_if_supported.cmake b/cmake/macros/macro_enable_if_supported.cmake
index 421b4fa1f4..b628b7a638 100644
--- a/cmake/macros/macro_enable_if_supported.cmake
+++ b/cmake/macros/macro_enable_if_supported.cmake
@@ -22,8 +22,15 @@
 #
 
 macro(enable_if_supported _variable _flag)
+  # First check if we can use -Werror
+  CHECK_CXX_COMPILER_FLAG("-Werror" DEAL_II_HAVE_FLAG_werror)
+
   string(STRIP "${_flag}" _flag_stripped)
 
+  if(DEAL_II_HAVE_FLAG_werror)
+    set(CMAKE_REQUIRED_FLAGS "-Werror")
+  endif()
+
   #
   # Gcc does not emit a warning if testing -Wno-... flags which leads to
   # false positive detection. Unfortunately it later warns that an unknown
@@ -47,5 +54,7 @@ macro(enable_if_supported _variable _flag)
       string(STRIP "${${_variable}}" ${_variable})
     endif()
   endif()
+
+  unset(CMAKE_REQUIRED_FLAGS)
 endmacro()