[Bug testsuite/85326] New: `make check` fails with `--disable-bootstrap` and `--enable-languages=c`

[edersondisouza at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85326

            Bug ID: 85326
           Summary: `make check` fails with `--disable-bootstrap` and
                    `--enable-languages=c`
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: testsuite
          Assignee: unassigned at gcc dot gnu.org
          Reporter: edersondisouza at hotmail dot com
  Target Milestone: ---

When building gcc from git tree (rev 03d52952b8ed93b676222f957c1a27a24cf3ef71),
`make check` fails if bootstrap is disabled and C is the only language enabled.

Compiled gcc -v output:

    ~/gcc-build-no-bootstrap$ gcc/xgcc -v
    Using built-in specs.
    COLLECT_GCC=gcc/xgcc
    Target: x86_64-pc-linux-gnu
    Configured with: ../gcc/configure --enable-languages=c --disable-bootstrap
--
    libdir=/opt/gcc/lib --prefix=/opt/gcc --libexecdir=/opt/gcc/libexec
    Thread model: posix
    gcc version 8.0.1 20180409 (experimental) (GCC) 

A bit more that one hundred tests fail, all with same message:

    C++ compiler not installed on this system.

A more detailed excerpt:

    Executing on host: /home/edesouza/gcc-build-no-bootstrap/gcc/xgcc
-B/home/edesouza/gcc-build-no-bootstrap/gcc/
/home/edesouza/gcc/gcc/testsuite/gcc.target/i386/mpx/chkp-thunk-comdat-1.cc 
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/ 
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxrt 
-L/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxrt/.libs
 -B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/ 
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxwrap 
-L/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxwrap/.libs
  -B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/ 
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxrt 
-L/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxrt/.libs
 -B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/ 
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxwrap 
-L/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxwrap/.libs
 -fno-diagnostics-show-caret -fdiagnostics-color=never    -O1  -O2
-fcheck-pointer-bounds -mmpx -S -o chkp-thunk-comdat-1.s    (timeout = 300)
spawn -ignore SIGHUP /home/edesouza/gcc-build-no-bootstrap/gcc/xgcc
-B/home/edesouza/gcc-build-no-bootstrap/gcc/
/home/edesouza/gcc/gcc/testsuite/gcc.target/i386/mpx/chkp-thunk-comdat-1.cc
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxrt
-L/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxrt/.libs
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxwrap
-L/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxwrap/.libs
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxrt
-L/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxrt/.libs
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/
-B/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxwrap
-L/home/edesouza/gcc-build-no-bootstrap/x86_64-pc-linux-gnu/./libmpx/mpxwrap/.libs
-fno-diagnostics-show-caret -fdiagnostics-color=never -O1 -O2
-fcheck-pointer-bounds -mmpx -S -o chkp-thunk-comdat-1.s
    xgcc: error:
/home/edesouza/gcc/gcc/testsuite/gcc.target/i386/mpx/chkp-thunk-comdat-1.cc:
C++ compiler not installed on this system
    compiler exited with status 1
    FAIL: gcc.target/i386/mpx/chkp-thunk-comdat-1.cc   -O1  (test for excess
errors)
    Excess errors:
    xgcc: error:
/home/edesouza/gcc/gcc/testsuite/gcc.target/i386/mpx/chkp-thunk-comdat-1.cc:
C++ compiler not installed on this system 

It appears that some tests, even depending on C++, are run and end up failing.
Note that when using bootstrap, tests execute fine [one unrelated test fail on
both], apparently due to the fact that gcc still build the C++ compiler despite
the `--enable-languages=c` flag.

If there's anything else I can provide to help, please let me know.