fftw: Build with ac_cv_func_clock_gettime=no

This avoid a problem with CLOCK_SGI_CYCLE not working on Android.

packages/fftw/build.sh

@@ -1,18 +1,22 @@
 TERMUX_PKG_HOMEPAGE=http://www.fftw.org/
 TERMUX_PKG_DESCRIPTION="Library for computing the Discrete Fourier Transform (DFT) in one or more dimensions"
 TERMUX_PKG_VERSION=3.3.6
-TERMUX_PKG_REVISION=1
+TERMUX_PKG_REVISION=2
 TERMUX_PKG_SRCURL=http://www.fftw.org/fftw-${TERMUX_PKG_VERSION}-pl1.tar.gz
 TERMUX_PKG_SHA256=1ef4aa8427d9785839bc767f3eb6a84fcb5e9a37c31ed77a04e7e047519a183d
-TERMUX_PKG_EXTRA_CONFIGURE_ARGS="--enable-threads"
+# ac_cv_func_clock_gettime=no avoids having clock_gettime(CLOCK_SGI_CYCLE, &t)
+# being used. It's not supported on Android but fails at runtime and, fftw
+# does not check the return value so gets bogus values.
+TERMUX_PKG_EXTRA_CONFIGURE_ARGS="--enable-threads ac_cv_func_clock_gettime=no"
 TERMUX_PKG_RM_AFTER_INSTALL="include/fftw*.f*"
 TERMUX_PKG_INCLUDE_IN_DEVPACKAGE="bin/ share/man/"
 
 termux_step_post_make_install() {
+	local COMMON_ARGS="$TERMUX_PKG_EXTRA_CONFIGURE_ARGS"
 	local feature
 	for feature in float long-double; do
 		make clean
-		TERMUX_PKG_EXTRA_CONFIGURE_ARGS="--enable-threads --enable-$feature"
+		TERMUX_PKG_EXTRA_CONFIGURE_ARGS="$COMMON_ARGS --enable-$feature"
 		rm -Rf $TERMUX_PKG_TMPDIR/config-scripts
 		termux_step_configure
 		make -j $TERMUX_MAKE_PROCESSES install