Merge branch 'rj/build-tweaks'

Merge branch 'rj/build-tweaks'

Various build tweaks, including CSPRNG selection on some platforms.

* rj/build-tweaks:
  config.mak.uname: set CSPRNG_METHOD to getrandom on Linux
  config.mak.uname: add arc4random to the cygwin build
  config.mak.uname: add sysinfo() configuration for cygwin
  builtin/gc.c: correct RAM calculation when using sysinfo
  config.mak.uname: add clock_gettime() to the cygwin build
  config.mak.uname: add HAVE_GETDELIM to the cygwin section
  config.mak.uname: only set NO_REGEX on cygwin for v1.7
  config.mak.uname: add a note about NO_STRLCPY for Linux
  Makefile: remove NEEDS_LIBRT build variable
  meson.build: set default help format to html on windows
  meson.build: only set build variables for non-default values
  Makefile: only set some BASIC_CFLAGS when RUNTIME_PREFIX is set
  meson.build: remove -DCURL_DISABLE_TYPECHECK