mpfr: cleanup patches

[ericLemanissier]

they were introduced in #14687 but never applied

also, use more compact archives

identified by #21146
and https://ericlemanissier.github.io/conan-center-lint-conandata/

Specify library name and version: lib/1.0

---

• I've read the contributing guidelines.
• I've used a recent Conan client version close to the currently deployed.
• I've tried at least one configuration locally with the conan-center hook activated.

[ericLemanissier]

The build is now finished. You can take a look at the results here

[conan-center-bot]

Conan v1 pipeline ✔️

All green in build 1 (ae150ff9e94dc8f0cf08fc42d82f9e443cb971aa):

• mpfr/4.2.1:
  All packages built successfully! (All logs)

• mpfr/4.1.0:
  All packages built successfully! (All logs)

• mpfr/4.2.0:
  All packages built successfully! (All logs)

• mpfr/4.0.2:
  All packages built successfully! (All logs)

---

Conan v2 pipeline ✔️

Note: Conan v2 builds are now mandatory. Please read our discussion about it.

All green in build 1 (ae150ff9e94dc8f0cf08fc42d82f9e443cb971aa):

• mpfr/4.2.1:
  All packages built successfully! (All logs)

• mpfr/4.2.0:
  All packages built successfully! (All logs)

• mpfr/4.1.0:
  All packages built successfully! (All logs)

• mpfr/4.0.2:
  All packages built successfully! (All logs)

[ericLemanissier]

for the record:
a 33.0% (718kB) smaller archive exists at https://ftp.gnu.org/gnu/mpfr/mpfr-4.2.1.tar.xz
a 33.0% (710kB) smaller archive exists at https://ftp.gnu.org/gnu/mpfr/mpfr-4.2.0.tar.xz
a 35.3% (812kB) smaller archive exists at https://ftp.gnu.org/gnu/mpfr/mpfr-4.1.0.tar.xz
a 34.8% (752kB) smaller archive exists at https://ftp.gnu.org/gnu/mpfr/mpfr-4.0.2.tar.xz

[uilianries]

I like to use .xz due its reduced size, but it requires xz-utils installed as well, so it's one more dependency. For Python >=3.3 it should not be a problem because lzma is already supported (Conan 2.x requires Python 3.5) https://docs.python.org/3/library/tarfile.html

I'm totally fine with this change, I just would not want to see PR only changing it, tar.gz is fine as well, are only few MBs more in total.

[uilianries]

LGTM