diff --git a/libc/calls/pledge-linux.c b/libc/calls/pledge-linux.c
index 368a91113..11d7e5bd7 100644
--- a/libc/calls/pledge-linux.c
+++ b/libc/calls/pledge-linux.c
@@ -977,13 +977,13 @@ static privileged void OnSigSys(int sig, siginfo_t *si, void *vctx) {
     if (HasSyscall(kPledge + i, si->si_syscall)) {
       Log("error: pledge ", kPledge[i].name, " for ",
           GetSyscallName(si->si_syscall), " (ord=", ord, " rip=", rip, ")\n",
-          0);
+          NULL);
       found = true;
     }
   }
   if (!found) {
     Log("error: bad syscall (", GetSyscallName(si->si_syscall), " ord=", ord,
-        " rip=", rip, ")\n", 0);
+        " rip=", rip, ")\n", NULL);
   }
   switch (mode & PLEDGE_PENALTY_MASK) {
     case PLEDGE_PENALTY_KILL_PROCESS:
diff --git a/libc/isystem/strings.h b/libc/isystem/strings.h
index 1c6fc89fb..6dcf85003 100644
--- a/libc/isystem/strings.h
+++ b/libc/isystem/strings.h
@@ -1,5 +1,6 @@
 #ifndef COSMOPOLITAN_LIBC_ISYSTEM_STRINGS_H_
 #define COSMOPOLITAN_LIBC_ISYSTEM_STRINGS_H_
+#include "libc/nexgen32e/ffs.h"
 #include "libc/str/locale.h"
 #include "libc/str/str.h"
 
diff --git a/libc/x/x.h b/libc/x/x.h
index 09cf0ba54..ae4a07cab 100644
--- a/libc/x/x.h
+++ b/libc/x/x.h
@@ -30,7 +30,7 @@ char *xstrndup(const char *, size_t) paramsnonnull()
     returnspointerwithnoaliases dontthrow nocallback dontdiscard returnsnonnull;
 char *xstrcat(const char *, ...) paramsnonnull((1)) nullterminated()
     returnspointerwithnoaliases dontthrow nocallback dontdiscard returnsnonnull;
-#define xstrcat(...) (xstrcat)(__VA_ARGS__, 0)
+#define xstrcat(...) (xstrcat)(__VA_ARGS__, NULL)
 char *xstrmul(const char *, size_t) paramsnonnull((1))
     returnspointerwithnoaliases dontthrow nocallback dontdiscard returnsnonnull;
 char *xinet_ntop(int, const void *) paramsnonnull()
diff --git a/libc/x/xjoinpaths.c b/libc/x/xjoinpaths.c
index 8dcdc863a..78deae1d4 100644
--- a/libc/x/xjoinpaths.c
+++ b/libc/x/xjoinpaths.c
@@ -43,6 +43,6 @@ char *xjoinpaths(const char *path, const char *other) {
   } else if (_endswith(path, "/")) {
     return xstrcat(path, other);
   } else {
-    return xstrcat(path, '/', other);
+    return xstrcat(path, (uintptr_t)'/', other);
   }
 }