Merge branch 'master' into core-updates

Note: this merge actually changes the 'curl' and 'python-attrs' derivations,
as part of solving caf4a7a277 and
12964df69a respectively.

4604d43c0e (gnu: gnutls@3.6.16: Fix cross-compilation.) was ignored because it
cannot currently be tested.

 Conflicts:
	gnu/local.mk
	gnu/packages/aidc.scm
	gnu/packages/boost.scm
	gnu/packages/curl.scm
	gnu/packages/nettle.scm
	gnu/packages/networking.scm
	gnu/packages/python-xyz.scm
	gnu/packages/tls.scm

gnu/packages/tex.scm

@@ -7011,7 +7011,7 @@ PDF documents.")
                        "texmaker.pro")))))))
     (inputs
      `(("poppler-qt5" ,poppler-qt5)
-       ("qtbase" ,qtbase)
+       ("qtbase" ,qtbase-5)
        ("qtscript" ,qtscript)
        ("qtwebkit" ,qtwebkit)
        ("zlib" ,zlib)))
@@ -7117,7 +7117,7 @@ and Karl Berry.")
        ("libx11" ,libx11)
        ("mythes" ,mythes)
        ("python" ,python)
-       ("qtbase" ,qtbase)
+       ("qtbase" ,qtbase-5)
        ("qtsvg" ,qtsvg)
        ("zlib" ,zlib)))
     (propagated-inputs