always define $FCCPP in QuantumESPRESSO easyblock (not just when using Intel compilers)

[boegel]

(created using eb --new-pr)

Fix for strange looking problem caused by $FCCPP not being defined when building QuantumESPRESSO 6.6 (or newer) using a GCC-based toolchain like gomkl:

( cd LAXlib ; make TLDEPS= all || exit 1 )
make[1]: Entering directory `/tmp/easybuild_build/QuantumESPRESSO/6.6/gomkl-2020a/qe-6.6/LAXlib'
I/software/imkl/2020.1.217-gompi-2020a/mkl/include -D__GFORTRAN -D__STD_F95 -D__MPI -D__PARA  -D__SCALAPACK -D__FFTW3 -w  -Duse_beef -I/tmp/easybuild_build/QuantumESPRESSO/6.6/gomkl-2020a/qe-6.6//include -I/tmp/easybuild_build/QuantumESPRESSO/6.6/gomkl-2020a/qe-6.6//FoX/finclude -I/tmp/easybuild_build/QuantumESPRESSO/6.6/gomkl-2020a/qe-6.6//S3DE/iotk/include/ -I/software/imkl/2020.1.217-gompi-2020a/mkl/include laxlib.h -o laxlib.fh                            
make[1]: I/software/imkl/2020.1.217-gompi-2020a/mkl/include: Command not found                                                                 
make[1]: [laxlib.fh] Error 127 (ignored)

[boegel]

Test report by @boegel

Overview of tested easyconfigs (in order)

• SUCCESS QuantumESPRESSO-6.6-intel-2019b.eb
• SUCCESS QuantumESPRESSO-6.3-foss-2018b.eb
• SUCCESS QuantumESPRESSO-6.5-intel-2019b.eb

Build succeeded for 3 out of 3 (3 easyconfigs in total)
node2400.golett.os - Linux centos linux 7.8.2003, x86_64, Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz (haswell), Python 2.7.5
See https://gist.github.com/05efdbc691cc09dd638b2e0a411cc10a for a full test report.

[boegel]

Test report by @boegel

Overview of tested easyconfigs (in order)

• SUCCESS imkl-2020.1.217-gompi-2020a.eb
• SUCCESS gomkl-2020a.eb
• SUCCESS QuantumESPRESSO-6.6-gomkl-2020a.eb

Build succeeded for 3 out of 3 (1 easyconfigs in total)
node2400.golett.os - Linux centos linux 7.8.2003, x86_64, Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz (haswell), Python 2.7.5
See https://gist.github.com/d99bc8674888c42bb3c24d0157eea1de for a full test report.

[migueldiascosta]

lgtm

[migueldiascosta]

Going in, thanks @boegel!