Fixes for the NAG Fortran compiler

[ACSimon33]

Description

There were several issues with using the NAG Fortran compiler in the new release:

• usage of non-standard IMAG function. I replaced it with AIMAG.
• missing check_fortran_compiler_flag macro include
• propagation of Fortran flags to the CBLAS subdirectory
• missing comma in FORMAT expression in the test framework

Checklist

• [n/a] The documentation has been updated.
• [n/a] If the PR solves a specific issue, it is set to be closed on merge.

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (cbb5536) 0.00% compared to head (2a0aea9) 0.00%.
Report is 1 commits behind head on master.

Files	Patch %	Lines
SRC/claqp2rk.f	0.00%	2 Missing ⚠️
SRC/claqp3rk.f	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #951   +/-   ##
=======================================
  Coverage    0.00%    0.00%           
=======================================
  Files        1930     1930           
  Lines      190055   190055           
=======================================
  Misses     190055   190055           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.