Android: add all arch support

Add support for armv7a, i686 and x86_64 archs to android.mk
Add -fPIC to depends file as anddroid requires it see https://stackoverflow.com/questions/30498776/position-independent-executables-and-android

depends/packages/qrencode.mk

@@ -8,6 +8,7 @@ define $(package)_set_vars
 $(package)_config_opts=--disable-shared --without-tools --without-tests --disable-sdltest
 $(package)_config_opts += --disable-gprof --disable-gcov --disable-mudflap
 $(package)_config_opts_linux=--with-pic
+$(package)_config_opts_android=--with-pic
 endef
 
 define $(package)_preprocess_cmds