ntdll: Use sysctl instead of /proc/curproc/file on FreeBSD.

dlls/ntdll/unix/loader.c

@@ -58,6 +58,10 @@
 #ifdef HAVE_SYS_WAIT_H
 #include <sys/wait.h>
 #endif
+#include <limits.h>
+#ifdef HAVE_SYS_SYSCTL_H
+# include <sys/sysctl.h>
+#endif
 #ifdef __APPLE__
 # include <CoreFoundation/CoreFoundation.h>
 # define LoadResource MacLoadResource
@@ -600,7 +604,14 @@ static void init_paths( char *argv[] )
 #if (defined(__linux__) && !defined(__ANDROID__)) || defined(__FreeBSD_kernel__) || defined(__NetBSD__)
         bin_dir = realpath_dirname( "/proc/self/exe" );
 #elif defined (__FreeBSD__) || defined(__DragonFly__)
-        bin_dir = realpath_dirname( "/proc/curproc/file" );
+        {
+            static int pathname[] = { CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1 };
+            size_t path_size = PATH_MAX;
+            char *path = malloc( path_size );
+            if (path && !sysctl( pathname, sizeof(pathname)/sizeof(pathname[0]), path, &path_size, NULL, 0 ))
+                bin_dir = realpath_dirname( path );
+            free( path );
+        }
 #else
         bin_dir = realpath_dirname( argv0 );
 #endif