fsync kernel build output

[stgeke]

Fixes #515

[codecov[bot]]

Codecov Report

Merging #520 (41a60f1) into main (9fc908f) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #520   +/-   ##
=======================================
  Coverage   76.25%   76.25%           
=======================================
  Files         263      263           
  Lines       19462    19469    +7     
=======================================
+ Hits        14841    14847    +6     
- Misses       4621     4622    +1     

Impacted Files	Coverage Δ
src/occa/internal/io/utils.cpp	97.75% <100.00%> (+0.08%)	:arrow_up:
src/occa/internal/modes/serial/device.cpp	90.81% <100.00%> (+0.04%)	:arrow_up:
src/occa/internal/lang/specialMacros.cpp	59.60% <0.00%> (-0.67%)	:arrow_down:
src/occa/internal/utils/sys.cpp	76.15% <0.00%> (-0.11%)	:arrow_down:

[stgeke]

Please let me know what it takes to merge this PR.

[kris-rowe]

Apologies for delay. The only thing I can see is that this may not be applicable in the Windows case, however adding some precompiler guards for now should likely be okay.

[stgeke]

May we can use this on Windows: https://docs.microsoft.com/en-gb/windows/win32/api/fileapi/nf-fileapi-flushfilebuffers?redirectedfrom=MSDN

[nnnunnn]

My Windows fork uses: int _commit(int fd);

https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/commit?view=msvc-160

From enable_msvc - occa/internal/io/utils.cpp line 471:

#if (OCCA_OS & (OCCA_LINUX_OS | OCCA_MACOS_OS))
      fsync(fileno(fp));
#else
      _commit(fileno(fp));        // NBN: VC++ compiler
#endif

[kris-rowe]

This PR has been updated in #638