core: Explicitly cast void* to char*

[jamesaimonetti]

When compiling a custom module, including shm_mem.h caused the
following compilation error:

In file included from ../../core/mem/shm_mem.h:32,
from custom_code.cpp:40:
../../core/parser/../ut.h: In function ‘char* shm_char_dup(const char*)’:
../../core/mem/shm.h:67:49: error: invalid conversion from ‘void*’ to ‘char*’ [-fpermissive]
67 | # define shm_malloc(s) _shm_root.xmalloc(_shm_root.mem_block, (s))
| ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
| |
| void*
../../core/parser/../ut.h:811:9: note: in expansion of macro ‘shm_malloc’
811 | rval = shm_malloc(len);
| ^~~~~~~~~~

gcc version: gcc (Debian 9.2.1-22) 9.2.1 20200104

Pre-Submission Checklist

• Commit message has the format required by CONTRIBUTING guide
• Commits are split per component (core, individual modules, libs, utils, ...)
• Each component has a single commit (if not, squash them into one commit)
• No commits to README files for modules (changes must be done to docbook files
  in doc/ subfolder, the README file is autogenerated)

Type Of Change

• Small bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds new functionality)
• Breaking change (fix or feature that would change existing functionality)

Checklist:

• PR should be backported to stable branches
• Tested changes locally
• Related to issue #XXXX (replace XXXX with an open issue number)

Description

[miconda]

Thanks! I pushed the patch manually, because the commit message was not formatted properly (the subject of PR has the format for the commit message):

• https://github.com/kamailio/kamailio/blob/master/.github/CONTRIBUTING.md#commit-message-rules

[jamesaimonetti]

@miconda thanks! Noted on the commit message. To clarify for me, what I put should have been a comment here on the PR and not in the commit message itself, yes?

[miconda]

It is about the first line of the commit messages which should be prefixed with the component name. The title of PR is:

core: Explicitly cast void* to char*

which is fine for first line of a commit message.

But your commit message had the first line:

Explicitly cast void* to char*

not indicating the component (core in this case).

You had another PR where the commit message was formatted ok.

[jamesaimonetti]

Ah right, I submitted the PR before reviewing the commit requirements, then editing the PR itself not the commit message. Thanks again for the feedback.