Makefile.PL Invokes $Config{cpp} instead of $Config{cpprun}

[kentfredric]

See Perl/perl5#17948

We've locally got perl configured with -Dcpp=$GCC -E, which is a perfectly valid C PreProcessor.

However, cpp only contains the "path" aspect of that, and strips the arguments.

https://github.com/Perl/perl5/blob/48a788454f1719093d08e80bbb70723ae345163a/Porting/Glossary#L315-L350

cpp (Loc.U):
	This variable is used internally by Configure to determine the
	full pathname (if any) of the cpp program.  After Configure runs,
	the value is reset to a plain "cpp" and is not useful.
...
cpprun (cppstdin.U):
	This variable contains the command which will invoke a C preprocessor
	on standard input and put the output to stdout. It is guaranteed not
	to be a wrapper and may be a null string if no preprocessor can be
	made directly available. This preprocessor might be different from the
	one used by the C compiler. Don't forget to append cpplast after the
preprocessor options.

#perl -V:cpp.*
cpp='x86_64-pc-linux-gnu-gcc';
cpp_stuff='42';
cppccsymbols='';
cppflags='-fwrapv -fno-strict-aliasing -pipe';
cpplast='-';
cppminus='-';
cpprun='x86_64-pc-linux-gnu-gcc  -E';
cppstdin='x86_64-pc-linux-gnu-gcc  -E';
cppsymbols='_FILE_OFFSET_BITS=64 _FORTIFY_SOURCE=2 _LARGEFILE_SOURCE=1 _LP64=1 _POSIX_C_SOURCE=200809L _POSIX_SOURCE=1 __BYTE_ORDER__=1234 __ELF__=1 __GLIBC_MINOR__=31 __GLIBC__=2 __GNUC_MINOR__=1 __GNUC__=10 __GNU_LIBRARY__=6 __LP64__=1 __PIC__=2 __STDC__=1 __USE_FILE_OFFSET64=1 __USE_LARGEFILE=1 __USE_MISC=1 __USE_POSIX199309=1 __USE_POSIX199506=1 __USE_POSIX2=1 __USE_POSIX=1 __amd64=1 __amd64__=1 __linux=1 __linux__=1 __pic__=2 __unix=1 __unix__=1 __x86_64=1 __x86_64__=1 linux=1 unix=1';

[jkeenan]

Addressed via 07778bf. Closing ticket. Thank you very much.