Openlibm

A list of issues that are related to the differences in math libraries among different systems:

bug #57071	Fix math.h and function names that block 64-bit double
bug #55538	logspace BIST tests fail when Octave built with LLVM libc++
bug #61968	pow2 with two arguments is not Matlab compatible
bug #62212	Wrong unsigned integer overflow with clang
bug #49984	fabs missing from libm implementation.
bug #61812	Math constants (e.g. M_PI) are not part of C/C++ standard
bug #49091	MinGW std::acosh less accurate than Linux versions
bug #61781	Eulers number wrong
bug #60784	Inconsistent behavior for boolean matrix types with matrix functions