less bad compiler warnings handling

examples/meson.build

@@ -20,7 +20,6 @@ foreach example: libostd_examples_src
         [example],
         dependencies: [libostd, thread_dep],
         include_directories: libostd_includes,
-        cpp_args: extra_cxxflags,
         install: false
     )
 endforeach

meson.build

@@ -1,6 +1,6 @@
 project('libostd', ['cpp'],
     version: '0.1.0',
-    default_options: ['buildtype=plain', 'cpp_std=c++17'],
+    default_options: ['buildtype=plain', 'cpp_std=c++17', 'warning_level=3'],
     meson_version: '>=0.46'
 )
 
@@ -15,15 +15,17 @@ unicode_data = join_paths('data', 'UnicodeData-11.0.txt')
 
 libostd_includes = [include_directories('.')]
 
-tgt_compiler_id = meson.get_compiler('cpp').get_id()
-if tgt_compiler_id == 'gcc' or tgt_compiler_id == 'clang'
-    extra_cxxflags = ['-Wextra', '-Wshadow', '-Wold-style-cast']
-else
-    extra_cxxflags = []
-endif
-
 cxx = meson.get_compiler('cpp')
 
+if get_option('buildtype') != 'plain'
+    if cxx.has_argument('-Wshadow')
+        add_global_arguments('-Wshadow', language: 'cpp')
+    endif
+    if cxx.has_argument('-Wold-style-cast')
+        add_global_arguments('-Wold-style-cast', language: 'cpp')
+    endif
+endif
+
 if cxx.has_argument('-fvisibility=hidden')
     add_global_arguments('-fvisibility=hidden', language: 'cpp')
 endif

src/meson.build

@@ -49,7 +49,7 @@ thread_dep = dependency('threads')
 libostd_gen_unicode_exe = executable('gen_unicode',
     ['../gen_unicode.cc'],
     include_directories: libostd_includes,
-    cpp_args: extra_cxxflags + ['-DOSTD_GEN_UNICODE_BUILD'],
+    cpp_args: ['-DOSTD_GEN_UNICODE_BUILD'],
     install: false,
     native: true
 )
@@ -70,7 +70,6 @@ libostd_lib = both_libraries('ostd',
     libostd_src, libostd_extra_src,
     dependencies: thread_dep,
     include_directories: libostd_includes + [include_directories('.')],
-    cpp_args: extra_cxxflags,
     install: true,
     version: meson.project_version()
 )

tests/meson.build

@@ -2,7 +2,6 @@ test_runner_exe = executable('test_runner',
     ['test_runner.cc'],
     dependencies: libostd,
     include_directories: libostd_includes,
-    cpp_args: extra_cxxflags,
     install: false
 )
 
@@ -40,7 +39,6 @@ foreach test_idx: libostd_tests_indices
         [libostd_tests_src[test_idx]],
         dependencies: libostd,
         include_directories: libostd_includes,
-        cpp_args: extra_cxxflags,
         install: false
     )
 endforeach