fixed gnu symbol visibility for static lib builds (fixes #201)

also:
- renamed header files to .hpp
- updated conformance tests
- minor documentation fixes

CHANGELOG.md

@@ -30,6 +30,14 @@ template:
 -   fixed error in README (#195) (@andrewkcorcoran)
 -   fixed compiler error when using NVCC (#198) (@thompsonnoahe)
 
+#### Changes:
+
+-   renamed header files to have `.hpp` extension (`toml.h` is still present for backwards-compatibility)
+
+#### Build system:
+
+-   fixed meson builds with `-Ddefault_library=static` having hidden symbols on GNU compilers (#201) (@vlad0x00)
+
 <br><br>
 
 ## v3.3.0

CONTRIBUTING.md

@@ -3,21 +3,21 @@
 Contributions are very welcome! Either by [reporting issues] or submitting pull requests.
 If you wish to submit a PR, please be aware that:
 
--   The single-header file `toml.hpp` is generated by a script; make your changes in the files in
-    `include`, **not** in `toml.hpp`.
+-   The single-header `toml.hpp` at the repository root is generated by a script, so don't change it directly; make your
+    changes in the files in `include`.
 -   Your changes should compile warning-free on at least one of:
     -   GCC 8 or higher
     -   Clang 8 or higher
     -   MSVC 19.2X (Visual Studio 2019) or higher
--   You should regenerate the single-header file as part of your PR (a CI check will fail if you don't).
+-   You should regenerate the single-header version of `toml.hpp` as part of your PR (a CI check will fail if you don't).
 
 <br>
 
-## Regenerating toml.hpp
+## Regenerating the single-header toml.hpp
 
 1. Make your changes as necessary
     - If you've added a new header file that isn't going to be transitively included by one of the
-      others, add an include directive to `include/toml++/toml.h`
+      others, add an include directive to `include/toml++/toml.hpp`
 2. Install the prerequisite python packages: `pip3 install -r tools/requirements.txt`
 3. Run `tools/generate_single_header.py`