configure.ac rework

- Put libusb and PC/SC check in m4 macros.
- Suppress --disable-pcsclite and --disable-libusb
- Add --with-drivers option: we now could choose which driver to build. without this option a default set is build (ATM all drivers except PN532_UART)

m4/libnfc_check_libusb.m4

@@ -0,0 +1,52 @@
+dnl Check for LIBUSB
+dnl On success, HAVE_LIBUSB is set to 1 and PKG_CONFIG_REQUIRES is filled when
+dnl libusb is found using pkg-config
+
+AC_DEFUN([LIBNFC_CHECK_LIBUSB],
+[
+  if test x"$libusb_required" = "xyes"; then
+    HAVE_LIBUSB=0
+  
+    # Search using pkg-config
+    if test x"$PKG_CONFIG" != "x"; then
+      PKG_CHECK_MODULES([libusb], [libusb], [HAVE_LIBUSB=1], [HAVE_LIBUSB=0])
+      if test x"$HAVE_LIBUSB" = "x1"; then
+        if test x"$PKG_CONFIG_REQUIRES" != x""; then
+          PKG_CONFIG_REQUIRES="$PKG_CONFIG_REQUIRES,"
+        fi
+        PKG_CONFIG_REQUIRES="$PKG_CONFIG_REQUIRES libusb"
+      fi
+    fi
+
+    AC_MSG_CHECKING(for libusb)
+  
+    # Search using libusb-config
+    if test x"$HAVE_LIBUSB" = "x0"; then
+      AC_PATH_PROG(libusb_CONFIG,libusb-config)
+      if test x"$libusb_CONFIG" != "x" ; then
+        libusb_CFLAGS=`$libusb_CONFIG --cflags`
+        libusb_LIBS=`$libusb_CONFIG --libs`
+        HAVE_LIBUSB=1
+      fi
+    fi
+  
+    # Search the library and headers directly (last chance)
+    if test x"$HAVE_LIBUSB" = "x0"; then
+      AC_CHECK_HEADER(usb.h, [], [AC_MSG_ERROR([The libusb headers are missing])])
+      AC_CHECK_LIB(usb, libusb_init, [], [AC_MSG_ERROR([The libusb library is missing])])
+  
+      libusb_LIBS="-lusb"
+      HAVE_LIBUSB=1
+    fi
+
+    if test x"$HAVE_LIBUSB" = "x0"; then
+      AC_MSG_RESULT(no)
+      AC_MSG_ERROR([libusb is mandatory.])
+    else
+      AC_MSG_RESULT(yes)
+    fi
+
+    AC_SUBST(libusb_LIBS)
+    AC_SUBST(libusb_CFLAGS)
+  fi
+])