65: Update `riscv` crate to version 0.6 r=Disasm a=luojia65

This pull request solves a probable version conflict between latest `riscv` and `riscv-rt`.

The MSRV is also updated to 1.42.0, since the 0.6.0 version of `riscv` crate requires 1.42.0: [link](https://github.com/rust-embedded/riscv/blob/6392fa9520b042bd559b00b9c7131b6de4189f89/CHANGELOG.md#changed

).

This pull request also includes a small typo fix in changelog file.



Co-authored-by: luojia65 <me@luojia.cc>

63: Release v0.7.2 r=almindor a=Disasm



Co-authored-by: Vadim Kaushan <admin@disasm.info>

61: Update link.x r=almindor a=richardeoin

Similar to #38, riscv compilers may also generate 'small ro data' `.srodata` sections. 

This doesn't appear to be well documented, but see [this blog post](https://www.sifive.com/blog/all-aboard-part-3-linker-relaxation-in-riscv-toolchain

) for small amount of context.

Co-authored-by: Richard Meadows <962920+richardeoin@users.noreply.github.com>

Similar to #38, riscv compilers may also generate 'small ro data' `.srodata` sections.

This doesn't appear to be well documented, but see [this blog post](https://www.sifive.com/blog/all-aboard-part-3-linker-relaxation-in-riscv-toolchain) for small amount of context.

62: Preserve .eh_frame and .eh_frame_hdr r=almindor a=Disasm

Preserving the `.eh_frame` section improves gdb stack traces on nightly.
Preserving the `.eh_frame_hdr` section fixes the linker problem `rust-lld: error: no memory region specified for section '.eh_frame_hdr'` introduced in https://github.com/rust-lang/rust/pull/73564



Co-authored-by: Vadim Kaushan <admin@disasm.info>

59: Release v0.7.1 r=Disasm a=khrs



Co-authored-by: Karol Harasim <karol.harasim@gmail.com>

Co-authored-by: Vadim Kaushan <admin@disasm.info>

Co-authored-by: Vadim Kaushan <admin@disasm.info>

58: Add hook to initialize custom interrupt controllers. r=Disasm a=khrs



Co-authored-by: Karol Harasim <karol.harasim@gmail.com>

Co-authored-by: Vadim Kaushan <admin@disasm.info>

57: Surround use of absolute address with "norelax" r=Disasm a=laanwj

This prevents an unsupported `R_RISCV_ALIGN` relocation from being generated by disabling link-time relaxing for the appropriate part.

Fixes #55.

Co-authored-by: Wladimir J. van der Laan <laanwj@protonmail.com>

This prevents an unsupported `R_RISCV_ALIGN` relocation from being
generated by disabling link-time relaxing for the appropriate part.

Fixes #55.

56: Exception handler may return r=Disasm a=laanwj

We need exceptions to be able to return. For example, after fixing the issue that caused them in the first place (e.g. paging), or after emulating missing instructions and possibly updating `mepc`.

Co-authored-by: Wladimir J. van der Laan <laanwj@protonmail.com>

54: Check code style on CI r=almindor a=Disasm



Co-authored-by: Vadim Kaushan <admin@disasm.info>

53: fix rust fmt to not mangle externs r=Disasm a=almindor

Cargo fmt mangled all the `extern "Rust"` cases, this fixes it and cleans up the code.

Co-authored-by: Ales Katona <ales@katona.me>

52: Only checking for necessary extensions when linking, made debug information location-independent r=almindor a=ilya-epifanov

Regarding the debug information:
```diff
1c1
< In archive src/oss/riscv-rt-orig/bin/riscv32i-unknown-none-elf.a:
---
> In archive src/oss/riscv-rt/bin/riscv32i-unknown-none-elf.a:
335,336c335,336
<     <18>   DW_AT_comp_dir    : (indirect string, offset: 0x6): /home/disasm/dev/rust/embedded/workspace/riscv-rt
<     <1c>   DW_AT_producer    : (indirect string, offset: 0x38): GNU AS 2.32
---
>     <18>   DW_AT_comp_dir    : (indirect string, offset: 0x6): /riscv-rt
>     <1c>   DW_AT_producer    : (indirect string, offset: 0x10): GNU AS 2.34
367,371c367,368
<   0x00000000 61736d2e 53002f68 6f6d652f 64697361 asm.S./home/disa
<   0x00000010 736d2f64 65762f72 7573742f 656d6265 sm/dev/rust/embe
<   0x00000020 64646564 2f776f72 6b737061 63652f72 dded/workspace/r
<   0x00000030 69736376 2d727400 474e5520 41532032 iscv-rt.GNU AS 2
<   0x00000040 2e333200                            .32.
---
>   0x00000000 61736d2e 53002f72 69736376 2d727400 asm.S./riscv-rt.
>   0x00000010 474e5520 41532032 2e333400          GNU AS 2.34.
386c383
<   Version:               1
---
>   Version:               3
```

Versions are still different, but at least the build paths are independent from the build environment.

Co-authored-by: Ilya Epifanov <elijah.epifanov@gmail.com>

51: CI fixes and improvements r=almindor a=Disasm



Co-authored-by: Vadim Kaushan <admin@disasm.info>

50: Document MSRV on README r=Disasm a=eldruin

See: https://github.com/rust-embedded/wg/issues/445



Co-authored-by: Diego Barrios Romero <eldruin@gmail.com>