as suggested by MigMuc in issue 2532

* Add an ARMV7 iOS build on Travis

* thread_local appears to be unavailable on ARMV7 iOS

* Add no-thumb option for ARMV7 IOS build to get it to accept DMB ISH

* Make local labels in macros of nrm2_vfpv3.S compatible with the xcode assembler

As noted in #1912 and comment on #1942, the combined implementation happens to "do the right thing" on hardfp, but cannot return both value and index on softfp where they would have to share the return register

(trivial copies of the respective ?asum with the fabs calls removed)

as suggested in #1990

second part of fix for #1774, containing files missed in #1775

fixes #1774

to pass the related utest (see #1469)

...to pass the related utest (see #1469)

The default arm/dot.c is less precise when used for DSDOT, as shown by utest

arm: Fix clang compilation for ARMv7

clang is not recognizing some pre-UAL VFP mnemonics like fnmacs, fnmacd,
fnmuls and fnmuld. Replaced them with equivalent UAL mnemonics which are
vmls.f32, vmls.f64, vnmul.f32 and vnmul.f64 respectively.

In case of softfp abi, assembly implementations of only those APIs are
used which doesnt have a floating point argument or return value.

In case of hard abi, all assembly implementations are used.

make ARM_SOFTFP_ABI=1