CMake: fix -Wint-conversion warning (error if clang is used as MPIC_C)

[band-a-prend]

Using of single quotes for printf argument within MPI_C check of CMakeLists.txt results in warning of conversion to int. The single quotes is used for char/int but not for char* type where the double quotes should be used.

If clang is used as MPI_C instead of gcc the configuration is failed with error:
incompatible integer to pointer conversion passing 'int' to parameter of type 'const char *' [-Wint-conversion]

(refer Gentoo [guru overlay] issue:https://bugs.gentoo.org/888009)

coverage on master

Summary of changes

Fix -Wint-conversion warning that results in CMake configuration error if clang is used as MPI_C compiler.

Rationale for changes

The presence of downstream issue (Gentoo Linux [guru overlay]): https://bugs.gentoo.org/888009

Additional info and certifications

This pull request (PR) is a:

• Bug fix
• Feature addition
• Other, Please describe:

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Code coverage data

[zbeekman]

LGTM, thanks and sorry for the slow response!

[zbeekman]

LGTM