Add Magnetic card emulation for C-Netz

Emulation can be done with a coil connected to sound card.

Alternatively an Attiny85 can be used to control a coil.

src/magnetic/Makefile.am

@@ -0,0 +1,28 @@
+AM_CPPFLAGS = -Wall -Wextra -g $(all_includes)
+
+bin_PROGRAMS = \
+	cnetz_magnetic
+
+cnetz_magnetic_SOURCES = \
+	iso7811.c \
+	image.c \
+	main.c
+
+cnetz_magnetic_LDADD = \
+	$(COMMON_LA) \
+	$(top_builddir)/src/libdebug/libdebug.a \
+	$(top_builddir)/src/liboptions/liboptions.a \
+	$(top_builddir)/src/libwave/libwave.a \
+	$(top_builddir)/src/libaaimage/libaaimage.a \
+	-lm
+
+if HAVE_ALSA
+cnetz_magnetic_LDADD += \
+        $(top_builddir)/src/libsound/libsound.a \
+        $(ALSA_LIBS)
+endif
+
+if HAVE_ALSA
+AM_CPPFLAGS += -DHAVE_ALSA
+endif
+