diff --git a/build-package.sh b/build-package.sh
index ad9361662..142d6c0cb 100755
--- a/build-package.sh
+++ b/build-package.sh
@@ -221,7 +221,7 @@ termux_step_setup_variables() {
 	TERMUX_STANDALONE_TOOLCHAIN="$TERMUX_TOPDIR/_lib/${TERMUX_NDK_VERSION}-${TERMUX_ARCH}-${TERMUX_API_LEVEL}"
 	# Bump the below version if a change is made in toolchain setup to ensure
 	# that everyone gets an updated toolchain:
-	TERMUX_STANDALONE_TOOLCHAIN+="-v3"
+	TERMUX_STANDALONE_TOOLCHAIN+="-v4"
 
 	export prefix=${TERMUX_PREFIX}
 	export PREFIX=${TERMUX_PREFIX}
@@ -370,6 +370,7 @@ termux_step_start_build() {
 	# Avoid exporting PKG_CONFIG_LIBDIR until after termux_step_host_build.
 	export TERMUX_PKG_CONFIG_LIBDIR=$TERMUX_PREFIX/lib/pkgconfig
 	# Add a pkg-config file for the system zlib.
+	mkdir -p "$TERMUX_PKG_CONFIG_LIBDIR"
 	cat > "$TERMUX_PKG_CONFIG_LIBDIR/zlib.pc" <<-HERE
 		Name: zlib
 		Description: zlib compression library
diff --git a/ndk-patches/pty.h.patch b/ndk-patches/pty.h.patch
new file mode 100644
index 000000000..68b7061bb
--- /dev/null
+++ b/ndk-patches/pty.h.patch
@@ -0,0 +1,18 @@
+In Termux these are implemented in the libutil package to support android-21.
+
+diff -u -r /home/fornwall/lib/android-ndk/sysroot/usr/include/pty.h ./usr/include/pty.h
+--- /home/fornwall/lib/android-ndk/sysroot/usr/include/pty.h	2017-06-20 17:41:56.000000000 +0200
++++ ./usr/include/pty.h	2017-07-02 11:42:39.244882732 +0200
+@@ -37,10 +37,8 @@
+ __BEGIN_DECLS
+ 
+ 
+-#if __ANDROID_API__ >= 23
+-int openpty(int*, int*, char*, const struct termios*, const struct winsize*) __INTRODUCED_IN(23);
+-int forkpty(int*, char*, const struct termios*, const struct winsize*) __INTRODUCED_IN(23);
+-#endif /* __ANDROID_API__ >= 23 */
++int openpty(int*, int*, char*, const struct termios*, const struct winsize*);
++int forkpty(int*, char*, const struct termios*, const struct winsize*);
+ 
+ 
+ __END_DECLS
diff --git a/ndk-patches/utmp.h.patch b/ndk-patches/utmp.h.patch
new file mode 100644
index 000000000..60e6ab374
--- /dev/null
+++ b/ndk-patches/utmp.h.patch
@@ -0,0 +1,18 @@
+In Termux login_tty() is implemented in the libutil package to support android-21.
+
+diff -u -r /home/fornwall/lib/android-ndk/sysroot/usr/include/utmp.h ./usr/include/utmp.h
+--- /home/fornwall/lib/android-ndk/sysroot/usr/include/utmp.h	2017-06-20 17:41:56.000000000 +0200
++++ ./usr/include/utmp.h	2017-07-02 11:42:29.724986159 +0200
+@@ -102,11 +102,6 @@
+ void endutent(void);
+ 
+ 
+-#if __ANDROID_API__ >= 23
+-int login_tty(int) __INTRODUCED_IN(23);
+-#endif /* __ANDROID_API__ >= 23 */
+-
+-
+-__END_DECLS
++int login_tty(int);
+ 
+ #endif /* _UTMP_H_ */
diff --git a/packages/libutil/build.sh b/packages/libutil/build.sh
index 1f1a73f67..8d94b7519 100644
--- a/packages/libutil/build.sh
+++ b/packages/libutil/build.sh
@@ -1,11 +1,10 @@
 TERMUX_PKG_HOMEPAGE=https://refspecs.linuxbase.org/LSB_2.1.0/LSB-generic/LSB-generic/libutil.html
 TERMUX_PKG_DESCRIPTION="Library with terminal functions"
-TERMUX_PKG_VERSION=0.2
+TERMUX_PKG_VERSION=0.3
 TERMUX_PKG_BUILD_IN_SRC=yes
 
 termux_step_make_install () {
-	CFLAGS+=" -std=c11"
-	$CC $CFLAGS -c -fPIC $TERMUX_PKG_BUILDER_DIR/pty.c -o pty.o
+	CPPFLAGS+=" -std=c11 -Wall -Werror"
+	$CC $CPPFLAGS $CFLAGS -c -fPIC $TERMUX_PKG_BUILDER_DIR/pty.c -o pty.o
 	$CC -shared -fPIC $LDFLAGS -o $TERMUX_PREFIX/lib/libutil.so pty.o
-	cp $TERMUX_PKG_BUILDER_DIR/pty.h $TERMUX_PREFIX/include/
 }
diff --git a/packages/libutil/pty.c b/packages/libutil/pty.c
index a2b89580e..435e75e91 100644
--- a/packages/libutil/pty.c
+++ b/packages/libutil/pty.c
@@ -7,7 +7,7 @@
 #include <unistd.h>
 
 
-int openpty(int* amaster, int* aslave, char* name, struct termios* termp, struct winsize* winp)
+int openpty(int* amaster, int* aslave, char* name, const struct termios* termp, const struct winsize* winp)
 {
 	char buf[512];
 
@@ -45,7 +45,7 @@ int login_tty(int fd)
 }
 
 
-int forkpty(int* amaster, char* name, struct termios* termp, struct winsize* winp)
+int forkpty(int* amaster, char* name, const struct termios* termp, const struct winsize* winp)
 {
 	int master, slave;
 	if (openpty(&master, &slave, name, termp, winp) == -1) {
diff --git a/packages/libutil/pty.h b/packages/libutil/pty.h
deleted file mode 100644
index 832c4e90c..000000000
--- a/packages/libutil/pty.h
+++ /dev/null
@@ -1,17 +0,0 @@
-#ifndef _PTY_H
-#define _PTY_H
-
-#include <sys/cdefs.h>
-#include <termios.h>
-
-__BEGIN_DECLS
-
-int openpty(int* amaster, int* aslave, char* name, struct termios* termp, struct winsize* winp);
-
-int login_tty(int fd);
-
-int forkpty(int* amaster, char* name, struct termios* termp, struct winsize* winp);
-
-__END_DECLS
-
-#endif
diff --git a/packages/ndk-sysroot/build.sh b/packages/ndk-sysroot/build.sh
index d18db4e1a..218a0f072 100644
--- a/packages/ndk-sysroot/build.sh
+++ b/packages/ndk-sysroot/build.sh
@@ -5,6 +5,9 @@ TERMUX_PKG_NO_DEVELSPLIT=yes
 # Depend on libandroid-support-dev so that iconv.h and libintl.h are available:
 TERMUX_PKG_DEPENDS="libandroid-support-dev"
 TERMUX_PKG_KEEP_STATIC_LIBRARIES="true"
+# This package has taken over <pty.h> from the previous libutil-dev:
+TERMUX_PKG_CONFLICTS="libutil-dev"
+TERMUX_PKG_REPLACES="libutil-dev"
 
 termux_step_extract_into_massagedir () {
 	mkdir -p $TERMUX_PKG_MASSAGEDIR/$TERMUX_PREFIX/lib/pkgconfig $TERMUX_PKG_MASSAGEDIR/$TERMUX_PREFIX/include