build: Also build 32-bit PowerPC Linux with -fpermissive

[glaubitz]

Fixes the build on 32-bit PowerPC which currently fails with:

FAILED: [code=1] src/CMakeFiles/kcov-system-daemon.dir/engines/ptrace_linux.cc.o
/usr/bin/c++ -DPACKAGE -DPACKAGE_VERSION -I/home/glaubitz/kcov/src/include -std=c++17 -g -Wall -D_GLIBCXX_USE_NANOSLEEP -DKCOV_LIBRARY_PREFIX=/tmp -DKCOV_HAS_LIBBFD=0 -DKCOV_LIBFD_DISASM_STYLED=0 -O3 -DNDEBUG -MD -MT src/CMakeFiles/kcov-system-daemon.dir/engines/ptrace_linux.cc.o -MF src/CMakeFiles/kcov-system-daemon.dir/engines/ptrace_linux.cc.o.d -o src/CMakeFiles/kcov-system-daemon.dir/engines/ptrace_linux.cc.o -c /home/glaubitz/kcov/src/engines/ptrace_linux.cc
In file included from /usr/lib/linux/uapi/powerpc/asm/sigcontext.h:12,
                 from /usr/include/powerpc-linux-gnu/bits/sigcontext.h:30,
                 from /usr/include/signal.h:301,
                 from /usr/include/powerpc-linux-gnu/sys/wait.h:36,
                 from /home/glaubitz/kcov/src/engines/ptrace_linux.cc:4:
/home/glaubitz/kcov/src/engines/ptrace_linux.cc: In function 'long int getRegs(pid_t, void*, void*, size_t)':
/home/glaubitz/kcov/src/engines/ptrace_linux.cc:334:23: error: invalid conversion from 'int' to '__ptrace_request' [-fpermissive]
  334 |         return ptrace(PTRACE_GETREGS, pid, NULL, regs);
      |                       ^~~~~~~~~~~~~~
      |                       |
      |                       int
In file included from /usr/include/powerpc-linux-gnu/sys/ptrace.h:285,
                 from /home/glaubitz/kcov/src/engines/ptrace_linux.cc:3:
/usr/include/powerpc-linux-gnu/bits/ptrace-shared.h:152:47: note: initializing argument 1 of 'long int ptrace(__ptrace_request, ...)'
  152 | extern long int ptrace (enum __ptrace_request __request, ...) __THROW;
      |                         ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~
/home/glaubitz/kcov/src/engines/ptrace_linux.cc: In function 'long int setRegs(pid_t, void*, void*, size_t)':
/home/glaubitz/kcov/src/engines/ptrace_linux.cc:382:23: error: invalid conversion from 'int' to '__ptrace_request' [-fpermissive]
  382 |         return ptrace(PTRACE_SETREGS, pid, NULL, regs);
      |                       ^~~~~~~~~~~~~~
      |                       |
      |                       int
/usr/include/powerpc-linux-gnu/bits/ptrace-shared.h:152:47: note: initializing argument 1 of 'long int ptrace(__ptrace_request, ...)'
  152 | extern long int ptrace (enum __ptrace_request __request, ...) __THROW;
      |                         ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~

Tested on 32- and 64-bit PowerPC, both little- and big-endian.

[glaubitz]

FWIW, the workaround is necessary due to a bug in glibc which has been reported upstream.

[SimonKagstrom]

Thanks! Didn't know it was an actual GCC bug, but good to know!

I see that the arch build fail with an internal compiler error for ppc64le. Still, one bug at a time :-)