diff -u -r /home/fornwall/lib/android-ndk/sysroot/usr/include/stdio.h ./usr/include/stdio.h
--- /home/fornwall/lib/android-ndk/sysroot/usr/include/stdio.h	2017-06-07 01:07:52.000000000 +0200
+++ ./usr/include/stdio.h	2017-06-18 01:59:17.835984565 +0200
@@ -44,6 +44,9 @@
 #include <stdarg.h>
 #include <stddef.h>
 
+#include <string.h>            /* For strcpy(3) used by ctermid() */
+#include <asm/fcntl.h>         /* For O_RDWR and other O_* constants */
+
 #define __need_NULL
 #include <stddef.h>
 
@@ -174,7 +178,7 @@
     __warnattr_strict("vsprintf is often misused; please use vsnprintf");
 char* tmpnam(char*)
     __warnattr("tempnam is unsafe, use mkstemp or tmpfile instead");
-#define P_tmpdir "/tmp/" /* deprecated */
+#define P_tmpdir "@TERMUX_PREFIX@/tmp/" /* deprecated */
 char* tempnam(const char*, const char*)
     __warnattr("tempnam is unsafe, use mkstemp or tmpfile instead");
 
@@ -239,8 +243,6 @@
   __INTRODUCED_IN(24);
 #endif /* __ANDROID_API__ >= 24 */
 
-FILE* tmpfile(void);
-
 #if __ANDROID_API__ >= 24
 FILE* tmpfile64(void) __INTRODUCED_IN(24);
 #endif /* __ANDROID_API__ >= 24 */
@@ -256,10 +258,15 @@
 
 #define L_ctermid 1024 /* size for ctermid() */
 
-#if __ANDROID_API__ >= 26
-char* ctermid(char*) __INTRODUCED_IN(26);
-#endif /* __ANDROID_API__ >= 26 */
+/* Needed by gnulibs freading() */
+#define __sferror(p)    (((p)->_flags & __SERR) != 0)
 
+/* Used by perl, fish, and others */
+static __inline__ char* ctermid(char* s) {
+    if (s == 0) return (char*) "/dev/tty";
+    strcpy(s, "/dev/tty");
+    return s;
+}
 
 FILE* fdopen(int, const char*);
 int fileno(FILE*);
@@ -577,4 +584,31 @@
 
 __END_DECLS
 
+__BEGIN_DECLS
+
+int open(const char*, int, ...) __overloadable __RENAME_CLANG(open);
+extern pid_t getpid();
+extern int unlink(const char*);
+void free(void* p);
+uint32_t arc4random(void);
+static __inline__ FILE* tmpfile() {
+	int p = getpid();
+	char* path;
+	int i;
+	for (i = 0; i < 100; i++) {
+		unsigned int r = arc4random();
+		if (asprintf(&path, "/data/data/com.termux/files/usr/tmp/tmpfile.%d-%u", p, r) == -1) return NULL;
+		int fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE, 0600);
+		free(path);
+		if (fd >= 0) {
+			FILE* result = fdopen(fd, "w+");
+			unlink(path);
+			return result;
+		}
+	}
+	return NULL;
+}
+
+__END_DECLS
+
 #endif /* _STDIO_H_ */