[Bug other/82590] auto-host.h error: declaration does not declare anything

[bastl at eclipso dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82590

--- Comment #1 from bastl <bastl at eclipso dot de> ---
Compiling gcc-7.2.0 with gcc-7.2.0
works fine.
What I did on this error and the other errors followed:
comment out the definitions cousing the errors like:

1.)
gcc/system.h:496:14: error: ambiguating new declaration of 'char* strstr(const
char*, const char*)'
 extern char *strstr (const char *, const char *);

2.)
gcc/system.h:540:20: error: conflicting declaration of C function 'const char*
strsignal(int)'
 extern const char *strsignal (int);
in the source directory in:

3.)
include/libiberty.h:112:14: error: ambiguating new declaration of 'char*
basename(const char*)'
 extern char *basename (const char *) ATTRIBUTE_RETURNS_NONNULL
ATTRIBUTE_NONNULL(1);

4.)
gcc/timevar.c:28:13: error: conflicting declaration 'typedef int clock_t'
 typedef int clock_t;

5.)
gcc/timevar.c:32:8: error: redefinition of 'struct tms'
 struct tms

then

# make -i

because all other errors don't matter to have a working gcc-7.2.0 compiler that
can compile itself.

# make -i install

and remake gcc itself.