[Bug c/95800] New: DJGPP 9.3.1 doesn't parse C files correctly

[teo.samarzija at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95800

            Bug ID: 95800
           Summary: DJGPP 9.3.1 doesn't parse C files correctly
           Product: gcc
           Version: 9.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: teo.samarzija at gmail dot com
  Target Milestone: ---

So, the C library I am using to cross-compile programs from Linux to DOS
apparently doesn't support the "log2" function, and I tried to polyfill it:

#include <math.h>

double log2(double x)
{
    return log(x)/log(2);
}

int main() {
    return 0;
}

However, when I do that, I get the following error, and the linking doesn't
even begin:
test.c:3:8: error: expected ')' before '/' token
    3 | double log2(double x)
      |        ^~~~

Here is what "djgpp-gcc -v" prints:
Using built-in specs.
COLLECT_GCC=djgpp-gcc
COLLECT_LTO_WRAPPER=/home/teo.samarzija/djgpp-9.3.0/libexec/gcc/djgpp/9.3.0/lto-wrapper
Target: djgpp
Configured with: ../gcc-9.3.0/configure --target=djgpp
--prefix=/home/teo.samarzija/djgpp-9.3.0
--enable-languages=c,c++,objc,ada,fortran,go
Thread model: single
gcc version 9.3.0 (GCC)