fftw3: improved to also build single and long-double precision libraries using seperate build loops

multimedia/fftw3/fftw3.conf

@@ -20,8 +20,23 @@
 [ "$arch" = "x86" ] && var_append confopt " " "--enable-i386-hacks"
 
 var_append confopt " " "--enable-threads"
-var_append confopt " " "--enable-float"
 
 if [ ! "`type -p f77`" ] ; then
     var_append confopt ' ' "--disable-fortran"
 fi
+
+# There are 3 APIs available which have to be build seperately
+# 1. double precision (default)
+# 2. single precision (--enable-single or --enable-float)
+# 3. long-double precision (--enable-long-double)
+buildloops=3
+
+pkg_fftw3_preconf() {
+	if [ $buildloop -eq 2 ]; then
+		var_append extraconfopt " " "--enable-float"
+	elif [ $buildloop -eq 3 ]; then
+		var_remove extraconfopt " " "--enable-float"
+		var_append extraconfopt " " "--enable-long-double"
+	fi
+}
+hook_add preconf 5 'pkg_fftw3_preconf'