fix Issue 10710 - phobos depends on versioned libcurl

- create a libcurl_stub.so for linking

- set it's soname to libcurl.so.4 so that phobos
  gets a DT_NEEDED libcurl.so.4 entry

- the runtime linker will load libcurl.so and resolve
  all undefined references

- disable pragma(lib, "curl") because it doesn't work
  for archives anyways and additionally links against
  the real libcurl (dmd appends -L-lcurl when building phobos).
Revert "Remove modules crc32 and std.md5 which had been deprecated by 6ff6adc5bf7d13b33e27985c53377cd20d7648e6"

This reverts commit ecbc04f90d21303fd72d9ecfd501df15f49515a2.
Merge pull request #1803 from monarchdodra/revertDeprecate

Revert "Remove modules crc32 and std.md5 which had been deprecated by 6f...
fix Issue 11789 - No setAttributes to complement getAttributes

[Issue 11789](https://d.puremagic.com/issues/show_bug.cgi?id=11789)
Revert "fix Issue 11789 - No setAttributes to complement getAttributes"

This reverts commit c124140e09d7acaa6cd6d4a4d677adf68fc08c55.
Merge pull request #1772 from MartinNowak/fix10710

fix Issue 10710 - phobos depends on versioned libcurl