make CC=other_cc in windows - c

Question

maybe this question is stupid but i really am not able to get a way to fix this i am trying to make a file in Cygwin64 i have all the dependency files installed, but when i make the file it throws me this
$ make
x86_64-w64-mingw32-gcc -D OS_WINDOWS_NT -ansi -Wall -O2 -Wno-long-long -I /usr/include -c -o main.o main.c
In file included from /usr/include/sys/_pthreadtypes.h:12,
from /usr/include/sys/types.h:223,
from /usr/include/stdio.h:61,
from main.c:5:
/usr/include/sys/cpuset.h:17:30: error: expected expression before ‘/’ token
17 | #define __CPU_SETSIZE 1024 // maximum number of logical processors tracked
| ^
/usr/include/sys/cpuset.h:19:25: note: in expansion of macro ‘__CPU_SETSIZE’
19 | #define __CPU_GROUPMAX (__CPU_SETSIZE / __NCPUBITS) // maximum group number
| ^~~~~~~~~~~~~
/usr/include/sys/cpuset.h:26:21: note: in expansion of macro ‘__CPU_GROUPMAX’
26 | __cpu_mask __bits[__CPU_GROUPMAX];
| ^~~~~~~~~~~~~~
/usr/include/sys/cpuset.h:19:55: error: expected expression before ‘/’ token
19 | #define __CPU_GROUPMAX (__CPU_SETSIZE / __NCPUBITS) // maximum group number
| ^
/usr/include/sys/cpuset.h:26:21: note: in expansion of macro ‘__CPU_GROUPMAX’
26 | __cpu_mask __bits[__CPU_GROUPMAX];
| ^~~~~~~~~~~~~~
/usr/include/sys/cpuset.h:27:1: warning: no semicolon at end of struct or union
27 | } cpu_set_t;
| ^
In file included from /usr/include/errno.h:9,
from main.c:8:
/usr/include/sys/errno.h:14: warning: "errno" redefined
14 | #define errno (*__errno())
|
In file included from /usr/lib/gcc/x86_64-w64-mingw32/10/include/stddef.h:1,
from /usr/include/sys/cdefs.h:47,
from /usr/include/stdio.h:35,
from main.c:5:
/usr/x86_64-w64-mingw32/sys-root/mingw/include/stddef.h:19: note: this is the location of the previous definition
19 | #define errno (*_errno())
|
make: *** [<builtin>: main.o] Error 1

Answer 1

Your problem is that you've added the -ansi option to your compile line:
x86_64-w64-mingw32-gcc -D OS_WINDOWS_NT -ansi ...
The -ansi option tells the compiler to compile your code as if it were ANSI C 89 standard code. That version of the standard did not support the // single-line comment delimiter: it only supports the traditional /* ... */ comments.
However the header file you're including clearly expects to be able to use // comments. So you cannot use the -ansi flag when you compile with these header files.