Require "classic ld" with XCODE 15.x on Mac

Fix division by zero in [z]rotg

Correct function prototypes in f2c-converted sources (lapack-netlib and ctest)

powerpc: Fix build errors with Open XL C

This patch fixes errors when using Open XL C compiler on AIX.
Tested with gcc/xlf and ibm-clang/xlf compiler combinations.

Improve function prototypes to fix strict-prototype warnings

Loongarch64 fixed dynamic arch

powerpc: Fix build errors with xlf

This patch fixes errors when using xlf as fortran compiler on Linux.
Tested with gcc/xlf and clang/xlf compiler combinations.

LoongArch64: Add dtrsm kernel

Fix building on POWER with IBM XLF 16.1.1

Fix handling of additional buffer structures in case of overflow

Set up arm64 graviton CI using cirun

* The check da != ZERO is no longer necessary since there
  is a special case ada == ZERO, where ada = |da|.
* Add the missing check c != ZERO before the division.

Note that with these two changes the long double code
follows the float/double version of the code.

The cases
[ c  s ] * [ 0      ] = [ |db_i| ]
[-s  c ]   [ i*db_i ]   [  0     ]
and
[ c  s ] * [ 0      ] = [ |db_r| ]
[-s  c ]   [ db_r   ]   [  0     ]
computed s incorrectly. To flip the entries of vector,
s should be conjg(db)/|db| and not conjg(db) / da,
where da == 0.0.