Merge branch 'wip/pwithnall/soft-c11-dependency' into 'main'

build: Add a soft dependency on C11

See merge request GNOME/glib!4473

CONTRIBUTING.md

@@ -120,7 +120,7 @@ development tools appropriate for your operating system, including:
  - Meson
  - Ninja
  - Gettext (19.7 or newer)
- - a [C99 compatible compiler](./docs/toolchain-requirements.md)
+ - a [compatible toolchain](./docs/toolchain-requirements.md)
 
 Up-to-date instructions about developing GNOME applications and libraries
 can be found on [the GNOME Developer Center](https://developer.gnome.org).

INSTALL.md

@@ -15,9 +15,8 @@ meson install -C _build                 # install GLib
 Requirements
 ============
 
-GLib requires a C90-compliant (but not necessarily C99-compliant) C
-compiler and libc. On UNIX-like systems, it also assumes compliance
-with at least the original 1990 version of POSIX.
+GLib requires a [basic C toolchain](./docs/toolchain-requirements.md) and
+support for a minimum version of the C standard.
 
 GLib-2.0 requires pkg-config, which is tool for tracking the
 compilation flags needed for libraries. (For each library, a small `.pc`

meson.build

@@ -25,6 +25,17 @@ foreach std : ['89', '99', '11', '17']
   endif
 endforeach
 
+# In the 2.85 cycle, this soft-dependency on C11 will become a hard dependency.
+# If this is a problem on your toolchain or platform, please file an issue
+# (https://gitlab.gnome.org/GNOME/glib/-/issues) and let us know. We have very
+# few metrics on the toolchains which are used to build GLib.
+if '11' not in c_standards
+  warning('Toolchain support for C11 will become a requirement for building ' +
+          'GLib in the next unstable development series (2.85). If this is ' +
+          'problematic for you, please file an issue ' +
+          '(https://gitlab.gnome.org/GNOME/glib/-/issues) now')
+endif
+
 have_cxx = add_languages('cpp', native: false, required: get_option('oss_fuzz').enabled())
 if have_cxx
   cxx = meson.get_compiler('cpp')