charmc: do not use pipes. They hide exit codes

[tvandera]

This is a proposed fix for https://github.com/UIUC-PPL/charm/issues/3785

[tvandera]

I will look into the failing CI

[tvandera]

The problem seems to be that the same files (e.g CkMarshall.decl.h) are generated multiple times from different Makefile rules.

$ grep CkMarshall 10_netlrts-linux-i386.txt                                                                                                                                              
2024-03-07T14:01:49.1683171Z [ 30%] Generating include/CkMarshall.decl.h, include/CkMarshall.def.h
2024-03-07T14:01:49.1778954Z [ 30%] Generating ../../include/CkMarshall.decl.h, ../../include/CkMarshall.def.h
2024-03-07T14:01:49.2437986Z make[2]: *** [src/ck-core/CMakeFiles/ck.dir/build.make:123: include/CkMarshall.decl.h] Error 1
2024-03-07T14:01:49.2439587Z make[2]: *** Deleting file 'include/CkMarshall.decl.h'
2024-03-07T14:02:00.6408806Z /home/runner/work/charm/charm/netlrts-linux-i386/include/ckmarshall.h:5:10: fatal error: CkMarshall.decl.h: No such file or directory
2024-03-07T14:02:00.6410638Z     5 | #include "CkMarshall.decl.h"
2024-03-07T14:02:00.6522825Z /home/runner/work/charm/charm/netlrts-linux-i386/include/ckmarshall.h:5:10: fatal error: CkMarshall.decl.h: No such file or directory
2024-03-07T14:02:00.6524385Z     5 | #include "CkMarshall.decl.h"

[tvandera]

Ready to be merged. Comments from @matthiasdiener addressed.