Squashed 'libs/cli11/' content from commit dcbcb47

git-subtree-dir: libs/cli11
git-subtree-split: dcbcb4721dda5dab0a56d9faaaee50e6a30f7758

cmake/CLI11Warnings.cmake

@@ -0,0 +1,37 @@
+# Special target that adds warnings. Is not exported.
+add_library(CLI11_warnings INTERFACE)
+
+set(unix-warnings -Wall -Wextra -pedantic -Wshadow -Wsign-conversion -Wswitch-enum)
+
+# Clang warnings
+# -Wfloat-equal could be added with Catch::literals and _a usage
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  list(
+    APPEND
+    unix-warnings
+    -Wcast-align
+    -Wimplicit-atomic-properties
+    -Wmissing-declarations
+    -Woverlength-strings
+    -Wshadow
+    -Wstrict-selector-match
+    -Wundeclared-selector)
+  # -Wunreachable-code Doesn't work on Clang 3.4
+endif()
+
+# Buggy in GCC 4.8
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.9)
+  list(APPEND unix-warnings -Weffc++)
+endif()
+
+target_compile_options(
+  CLI11_warnings
+  INTERFACE $<$<BOOL:${CLI11_FORCE_LIBCXX}>:-stdlib=libc++>
+            $<$<CXX_COMPILER_ID:MSVC>:/W4
+            $<$<BOOL:${CLI11_WARNINGS_AS_ERRORS}>:/WX>>
+            $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:${unix-warnings}
+            $<$<BOOL:${CLI11_WARNINGS_AS_ERRORS}>:-Werror>>)
+
+if(NOT CMAKE_VERSION VERSION_LESS 3.13)
+  target_link_options(CLI11_warnings INTERFACE $<$<BOOL:${CLI11_FORCE_LIBCXX}>:-stdlib=libc++>)
+endif()