Basically, mirror the following two commits from modlib.
It's shame we have two copies of elf loaders.
```
commit 51490bad551737ce8210c196ce962fd28121a97d
Author: YAMAMOTO Takashi <yamamoto@midokura.com>
Date: Wed Apr 14 17:07:39 2021 +0900
modlib: Implement sh_addralign handling
I've seen a module with 16 bytes .rodata alignment for xmm operations.
It was getting SEGV on sim/Linux because of the alignment issue.
The same module binary seems working fine after applying this patch.
Also, tested on sim/macOS and esp32 on qemu,
using a module with an artificially large alignment. (64 bytes)
```
```
commit 418e11b8b38855eacf55deea8d658c5760b51488
Author: YAMAMOTO Takashi <yamamoto@midokura.com>
Date: Thu Apr 15 11:33:48 2021 +0900
modlib: Always use separate allocation for text and data
Pros:
* Reduce code differences
* Smaller allocations for !CONFIG_ARCH_USE_MODULE_TEXT
Cons:
* Likely to use more memory for !CONFIG_ARCH_USE_MODULE_TEXT in total
Tested with:
* sim:module on macOS
* esp32-devkit:nsh + CONFIG_MODULE on qemu
* lm3s6965-ek:qemu-protected + CONFIG_EXAMPLES_SOTEST on qemu
```
e596d5bd5e