Ticket #1774: Various build fixups (missing includes, name clashes, ...)

m4.include/ac-get-fs-info.m4: fixed const char* issue which triggers break on -Wall

Signed-off-by: Slava Zanko <slavazanko@gmail.com>

m4.include/ac-get-fs-info.m4

@@ -142,7 +142,7 @@ if test x"$ac_cv_func_getmntent" = xyes; then
 # endif
 #endif
 ],
-                    [ struct mntent *mnt = 0; char *table = MOUNTED;
+                    [ struct mntent *mnt = 0; const char *table = MOUNTED;
 		      if (sizeof mnt && sizeof table) return 0;],
 		    fu_cv_sys_mounted_getmntent1=yes,
 		    fu_cv_sys_mounted_getmntent1=no)])