libga68: Remove redundant attribute visibility check macro.
The libga68 library now uses the shared GCC macro for checking attribute visibility.
This commit removes a redundant macro, CHECK_ATTRIBUTE_VISIBILITY, from libga68 and replaces it with the shared GCC macro from config/visibility.m4. This change simplifies the build process and promotes consistency across the GCC project.
In Details
The libga68 library provides support for the 68000 family of processors. This commit removes the custom LIBGA68_CHECK_ATTRIBUTE_VISIBILITY macro in acinclude.m4 and uses the standard GCC_CHECK_ATTRIBUTE_VISIBILITY defined in config/visibility.m4. This change reduces code duplication and relies on the central definition for attribute visibility checks.
For Context
Autotools macros help to ensure that software can be built on a wide variety of systems. They check for the presence of certain features and define variables that are used during the build process. This commit removes a custom autotools macro from the libga68 library and replaces it with a standard macro from GCC, promoting consistency and simplifying maintenance.