package/fftw: add fortran support

Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
[Thomas: pass FLIBS explicitly to help the configure script.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/fftw/fftw.mk

@@ -10,7 +10,13 @@ FFTW_INSTALL_STAGING = YES
 FFTW_LICENSE = GPLv2+
 FFTW_LICENSE_FILES = COPYING
 
-FFTW_CONF_OPTS = --disable-fortran
+# fortran support only enables generation and installation of fortran sources
+ifeq ($(BR2_TOOLCHAIN_HAS_FORTRAN),y)
+FFTW_CONF_OPTS += --enable-fortran
+FFTW_CONF_ENV += FLIBS="-lgfortran -lm"
+else
+FFTW_CONF_OPTS += --disable-fortran
+endif
 
 FFTW_CONF_OPTS += $(if $(BR2_PACKAGE_FFTW_PRECISION_SINGLE),--enable,--disable)-single
 FFTW_CONF_OPTS += $(if $(BR2_PACKAGE_FFTW_PRECISION_LONG_DOUBLE),--enable,--disable)-long-double