testsuite: add file system test suite test_symlinks.sh

src/conf.h

@@ -187,13 +187,15 @@ typedef upx_int64_t upx_off_t;
 #undef small
 #undef tos
 #undef unix
-#if defined(__linux__) && !defined(__unix__)
+#if (ACC_OS_POSIX) && !defined(__unix__)
 #  define __unix__ 1
 #endif
+#if (ACC_OS_CYGWIN || ACC_OS_DOS16 || ACC_OS_DOS32 || ACC_OS_EMX || ACC_OS_OS2 || ACC_OS_OS216 || ACC_OS_WIN16 || ACC_OS_WIN32 || ACC_OS_WIN64)
+#  undef __unix
+#  undef __unix__
+#endif
 #if (ACC_OS_DOS32) && defined(__DJGPP__)
 #  undef sopen
-#  undef __unix
-#  undef __unix__
 #endif
 
 #if defined(HAVE_DUP) && (HAVE_DUP + 0 == 0)

src/help.cpp

@@ -225,7 +225,7 @@ void show_help(int verbose) {
         fg = con_fg(f, fg);
         con_fprintf(f,
                     "  --force-overwrite   force overwrite of output files\n"
-#if defined(__unix__) && !defined(__MSYS2__)
+#if defined(__unix__)
                     "  --link              preserve hard links (Unix only) [USE WITH CARE]\n"
                     "  --no-link           do not preserve hard links but rename files [default]\n"
 #endif

src/main.cpp

@@ -201,7 +201,8 @@ static void check_and_update_options(int i, int argc) {
     check_not_both(opt->force_overwrite, opt->preserve_link, "--force-overwrite", "--link");
     check_not_both(opt->to_stdout, opt->preserve_link, "--stdout", "--link");
 
-#if defined(__unix__) && !defined(__MSYS2__)
+#if defined(__unix__)
+    static_assert(HAVE_LSTAT);
 #else
     // preserve_link is currently silently ignored on non-Unix platforms
     // (we may revisit this decision later if there is some actual use-case)

src/p_unix.cpp

@@ -72,7 +72,7 @@ tribool PackUnix::canPack()
     if (exetype == 0)
         return false;
 
-#if defined(__unix__) && !defined(__MSYS2__)
+#if defined(__unix__)
     // must be executable by owner
     if ((fi->st.st_mode & S_IXUSR) == 0)
         throwCantPack("file not executable; try 'chmod +x'");