[PATCH] trace/wscript: Improve C++ standard selection

[Sebastian Huber]

Use the latest C++ standard available up to C++20.

Close #4908.
---
 trace/wscript | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/trace/wscript b/trace/wscript
index a3dd5d5..adabd5f 100644
--- a/trace/wscript
+++ b/trace/wscript
@@ -45,7 +45,14 @@ def configure(conf):
     if conf.check(header_name='zlib.h', features='cxx', mandatory=False):
         conf.check_cxx(lib = 'z')
     conf.check_cxx(lib = 'ws2_32', mandatory=False)
-    conf.check_cxx(cxxflags='-std=c++14', mandatory=False, define_name="HAVE_STD_CXX14")
+    if conf.check_cxx(cxxflags='-std=c++20', mandatory=False, define_name="HAVE_STD_CXX20"):
+        conf.env.append_value('CXXFLAGS', '-std=c++20')
+    elif conf.check_cxx(cxxflags='-std=c++17', mandatory=False, define_name="HAVE_STD_CXX17"):
+        conf.env.append_value('CXXFLAGS', '-std=c++17')
+    elif conf.check_cxx(cxxflags='-std=c++14', mandatory=False, define_name="HAVE_STD_CXX14"):
+        conf.env.append_value('CXXFLAGS', '-std=c++14')
+    else:
+        conf.env.append_value('CXXFLAGS', '-std=c++11')
     conf.write_config_header('config.h')
 
 def build(bld):
@@ -62,9 +69,14 @@ def build(bld):
     conf['optflags'] = bld.env.C_OPTS
     cstd = '-std=c99'
     conf['cflags'] = [cstd] + ['-pipe', '-g'] + conf['optflags']
-    cxxstd = '-std=c++11'
-    if bld.env.HAVE_STD_CXX14:
+    if bld.env.HAVE_STD_CXX20:
+        cxxstd = '-std=c++20'
+    elif bld.env.HAVE_STD_CXX17:
+        cxxstd = '-std=c++17'
+    elif bld.env.HAVE_STD_CXX14:
         cxxstd = '-std=c++14'
+    else:
+        cxxstd = '-std=c++11'
     conf['cxxflags'] = [cxxstd] + ['-pipe', '-g'] + conf['optflags']
     conf['linkflags'] = ['-g']
     conf['lib'] = []
-- 
2.35.3