remove unnecessary workaround for fclose() on OpenBSD

proxychains-ng didn't call fclose() in a particular FILE on OpenBSD if a
test in the Makefile noticed that OpenBSD's fclose() called close() on
the underlying fd of the FILE.

The test hasn't worked for 8 years because an OpenBSD commit prevented
the test from overriding the libc close():
https://cvsweb.openbsd.org/src/lib/libc/stdio/fclose.c?rev=1.10&content-type=text/x-cvsweb-markup
>let internal calls resolve directly and not be overridable
For all this time, the workaround wasn't doing anything.

Additionally, behavior equivalent to calling close() on a fd is
mandatory in POSIX:
https://pubs.opengroup.org/onlinepubs/9699919799.2008edition/
>The fclose() function shall perform the equivalent of a close()
>on the file descriptor

And finally, at least NetBSD 9.3 also uses the close() function to do
the same, but there's no workaround, and no reported misbehavior when
running on NetBSD to work around.

Even if the test did work, all the workaround appears to do is leak a
FILE.

Author: guijan

configure

@@ -220,9 +220,6 @@ check_define __FreeBSD__ && bsd_detected=true
 check_define __OpenBSD__ && {
 bsd_detected=true
 echo "CFLAGS+=-DIS_OPENBSD">>config.mak
-check_compile_run 'whether OpenBSDs fclose() (illegally) calls close()' \
-'#include <stdio.h>\n#include<stdlib.h>\nint close(int x){exit(0);}int main(){fclose(stdin);return 1;}' && \
-OUR_CPPFLAGS="$OUR_CPPFLAGS -DBROKEN_FCLOSE"
 }
 check_define __sun && check_define __SVR4 && solaris_detected=true
 check_define __HAIKU__ && haiku_detected=true

src/libproxychains.c

@@ -115,7 +115,7 @@ typedef struct {
 	unsigned int first, last, flags;
 } close_range_args_t;
 
-/* If there is some `close` or `close_range` system call before do_init, 
+/* If there is some `close` or `close_range` system call before do_init,
    we buffer it, and actually execute them in do_init. */
 static int close_fds[16];
 static int close_fds_cnt = 0;
@@ -560,9 +560,7 @@ static void get_chain_data(proxy_data * pd, unsigned int *proxy_count, chain_typ
 			}
 		}
 	}
-#ifndef BROKEN_FCLOSE
 	fclose(file);
-#endif
 	if(!count) {
 		fprintf(stderr, "error: no valid proxy found in config\n");
 		exit(1);
@@ -639,7 +637,7 @@ HOOKFUNC(int, close_range, unsigned first, unsigned last, int flags) {
 	int protected_fds[] = {req_pipefd[0], req_pipefd[1], resp_pipefd[0], resp_pipefd[1]};
 	intsort(protected_fds, 4);
 	/* We are skipping protected_fds while calling true_close_range()
-	 * If protected_fds cut the range into some sub-ranges, we close sub-ranges BEFORE cut point in the loop. 
+	 * If protected_fds cut the range into some sub-ranges, we close sub-ranges BEFORE cut point in the loop.
 	 * [first, cut1-1] , [cut1+1, cut2-1] , [cut2+1, cut3-1]
 	 * Finally, we delete the remaining sub-range, outside the loop. [cut3+1, tail]
 	 */