diff --git a/libc/isystem/unistd.h b/libc/isystem/unistd.h
index 942c30e74..78b62edb9 100644
--- a/libc/isystem/unistd.h
+++ b/libc/isystem/unistd.h
@@ -10,12 +10,8 @@
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/consts/ok.h"
 #include "libc/time/time.h"
+#include "libc/unistd.h"
 #include "third_party/getopt/long1.h"
 #include "third_party/musl/crypt.h"
 #include "third_party/musl/lockf.h"
-
-#ifndef _CS_PATH
-#define _CS_PATH 0
-#endif
-
 #endif /* _UNISTD_H */
diff --git a/libc/stdio/confstr.c b/libc/stdio/confstr.c
index 16b88dcfd..735b9589d 100644
--- a/libc/stdio/confstr.c
+++ b/libc/stdio/confstr.c
@@ -20,6 +20,7 @@
 #include "libc/stdio/stdio.h"
 #include "libc/str/str.h"
 #include "libc/sysv/errfuns.h"
+#include "libc/unistd.h"
 
 size_t confstr(int name, char *buf, size_t len) {
   if (name == _CS_PATH) {
diff --git a/libc/stdio/stdio.h b/libc/stdio/stdio.h
index 021aa7c3a..4d385e0ba 100644
--- a/libc/stdio/stdio.h
+++ b/libc/stdio/stdio.h
@@ -1,12 +1,11 @@
 #ifndef COSMOPOLITAN_LIBC_STDIO_H_
 #define COSMOPOLITAN_LIBC_STDIO_H_
 
-#define EOF      -1  /* end of file */
-#define WEOF     -1u /* end of file (multibyte) */
-#define _IOFBF   0   /* fully buffered */
-#define _IOLBF   1   /* line buffered */
-#define _IONBF   2   /* no buffering */
-#define _CS_PATH 0
+#define EOF    -1  /* end of file */
+#define WEOF   -1u /* end of file (multibyte) */
+#define _IOFBF 0   /* fully buffered */
+#define _IOLBF 1   /* line buffered */
+#define _IONBF 2   /* no buffering */
 
 #define L_tmpnam     20
 #define L_ctermid    20
diff --git a/libc/stdlib.h b/libc/stdlib.h
index 9c5bc3b1e..e7ef213f0 100644
--- a/libc/stdlib.h
+++ b/libc/stdlib.h
@@ -6,5 +6,10 @@ char *fcvt(double, int, int *, int *) libcesque;
 char *ecvt(double, int, int *, int *) libcesque;
 char *gcvt(double, int, char *) libcesque;
 
+#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) || defined(_BSD_SOURCE) || \
+    defined(_COSMO_SOURCE)
+void setkey(const char *) libcesque;
+#endif
+
 COSMOPOLITAN_C_END_
 #endif /* COSMOPOLITAN_LIBC_STDLIB_H_ */
diff --git a/libc/unistd.h b/libc/unistd.h
new file mode 100644
index 000000000..04bf9c95a
--- /dev/null
+++ b/libc/unistd.h
@@ -0,0 +1,14 @@
+#ifndef COSMOPOLITAN_LIBC_UNISTD_H_
+#define COSMOPOLITAN_LIBC_UNISTD_H_
+COSMOPOLITAN_C_START_
+
+#define _CS_PATH 0
+
+#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) || defined(_BSD_SOURCE) || \
+    defined(_COSMO_SOURCE)
+void encrypt(char *, int) libcesque;
+char *crypt(const char *, const char *) libcesque;
+#endif
+
+COSMOPOLITAN_C_END_
+#endif /* COSMOPOLITAN_LIBC_UNISTD_H_ */
diff --git a/third_party/musl/crypt.h b/third_party/musl/crypt.h
index 111c445e8..5fc464f9d 100644
--- a/third_party/musl/crypt.h
+++ b/third_party/musl/crypt.h
@@ -7,10 +7,8 @@ struct crypt_data {
   char __buf[256];
 };
 
-void encrypt(char *, int);
-void setkey(const char *);
-char *crypt(const char *, const char *);
-char *crypt_r(const char *, const char *, struct crypt_data *);
+char *crypt(const char *, const char *) libcesque;
+char *crypt_r(const char *, const char *, struct crypt_data *) libcesque;
 
 COSMOPOLITAN_C_END_
 #endif /* COSMOPOLITAN_THIRD_PARTY_MUSL_CRYPT_H_ */
diff --git a/third_party/python/Modules/posixmodule.c b/third_party/python/Modules/posixmodule.c
index 98d55bd8f..fee776524 100644
--- a/third_party/python/Modules/posixmodule.c
+++ b/third_party/python/Modules/posixmodule.c
@@ -89,6 +89,7 @@
 #include "third_party/python/Include/warnings.h"
 #include "third_party/python/Include/yoink.h"
 #include "third_party/python/Modules/_multiprocessing/multiprocessing.h"
+#include "libc/unistd.h"
 #include "third_party/python/pyconfig.h"
 
 PYTHON_PROVIDE("posix");
diff --git a/tool/cosmocc/package.sh b/tool/cosmocc/package.sh
index 8f43c94fb..180ea8f9c 100755
--- a/tool/cosmocc/package.sh
+++ b/tool/cosmocc/package.sh
@@ -130,7 +130,7 @@ for arch in $AMD64 $ARM64; do
   cp -f o/$arch/libc/crt/crt.o "$OUTDIR/$arch-linux-cosmo/lib/"
   cp -f o/$arch/cosmopolitan.a "$OUTDIR/$arch-linux-cosmo/lib/libcosmo.a"
   cp -f o/$arch/third_party/libcxx/libcxx.a "$OUTDIR/$arch-linux-cosmo/lib/"
-  for lib in c dl gcc_s m pthread resolv rt dl unwind gomp stdc++; do
+  for lib in c dl gcc_s m crypt pthread resolv rt dl unwind gomp stdc++; do
     printf '\041\074\141\162\143\150\076\012' >"$OUTDIR/$arch-linux-cosmo/lib/lib$lib.a"
   done
   mkdir -p "$OUTDIR/lib/gcc/"