Fixing build error with mimalloc.h, where size_t definition is not included

[JadenMajid]

Build error: size_t is defined in stddef.h but stddef.h was not included
Change: included stddef.h to the mimalloc.h file to resolve lack of definition

[StefanJum]

Hi @JadenMajid, please update the commit message to something more desriptive (e.g. Add the stddef.hheader tomimalloc.h`)

[JadenMajid]

@StefanJum Updated the commit message

[StefanJum]

@JadenMajid You need to update the commit message using git commit --amend and then do a git push --force, just updating the PR description will not work.

[JadenMajid]

@StefanJum I did as you advised, can you confirm if it worked?

[StefanJum]

@JadenMajid the commit still did not update, you can check it under the commits page https://github.com/unikraft/lib-mimalloc/pull/10/commits

[razvand]

@JadenMajid , please see the comment from @StefanJum .