Update the build support of the included PCRE as we are now including
PCRE 8.30 with the GLib distribution.
Also "install" the new gversionmacros.h header file.
The way gtk-doc works, we need compiling.sgml in both
content_files (to make sure it ends up in the disted tarball)
and in expand_content_files (to have references expanded).
The version number we have here is the one the function appeared
in, not the max-allowed version. Therefore 'unavailable before
VERSION' makes more sense than 'unavailable for VERSION'.
There are cases when it should be possible to define at compile time
what range of functions and types should be used, in order to get,
or restrict, the compiler warnings for deprecated or newly added
types or functions.
For instance, if GLib introduces a deprecation warning on a type in
version 2.32, application code can decide to specify the minimum and
maximum boundary of the used API to be 2.30; when compiling against
a new version of GLib, this would produce the following results:
- all deprecations introduced prior to 2.32 would emit compiler
warnings when used by the application code;
- all deprecations introduced in 2.32 would not emit compiler
warnings when used by the application code;
- all new symbols introduced in 2.32 would emit a compiler warning.
Using this scheme it should be possible to have fairly complex
situations, like the following one:
assuming that an application is compiled with:
GLIB_VERSION_MIN_REQUIRED = GLIB_VERSION_2_30
GLIB_VERSION_MAX_ALLOWED = GLIB_VERSION_2_32
and a GLib header containing:
void function_A (void) GLIB_DEPRECATED_IN_2_26;
void function_B (void) GLIB_DEPRECATED_IN_2_28;
void function_C (void) GLIB_DEPRECATED_IN_2_30;
void function_D (void) GLIB_AVAILABLE_IN_2_32;
void function_E (void) GLIB_AVAILABLE_IN_2_34;
any application code using the above functions will get the following
compiler warnings:
function_A: deprecated symbol warning
function_B: deprecated symbol warning
function_C: no warning
function_D: no warning
function_E: undefined symbol warning
This means that it should be possible to gradually port code towards
non-deprecated API gradually, on a per-release basis.
https://bugzilla.gnome.org/show_bug.cgi?id=670542
