Fix typo.

Add doxygen detection and --enable-doc flag to ./configure.

configure.ac

@@ -65,7 +65,7 @@ AC_MSG_RESULT($enable_pcsc_lite)
  
 if test x"$enable_pcsc_lite" = "xno"
 then
-        WITH_PCSC=0
+  WITH_PCSC=0
 fi
 AM_CONDITIONAL(PCSC_LITE_ENABLED, [test x"$enable_pcsc_lite" = xyes])
 
@@ -75,12 +75,31 @@ AC_ARG_ENABLE([libusb],AS_HELP_STRING([--disable-libusb],[Disable libusb depende
 AC_MSG_CHECKING(for libusb support)
 AC_MSG_RESULT($enable_libusb)
  
-if test x"$enable_libsub" = "xno"
+if test x"$enable_libusb" = "xno"
 then
-        WITH_LIBUSB=0
+  WITH_LIBUSB=0
 fi
 AM_CONDITIONAL(LIBUSB_ENABLED, [test x"$enable_libusb" = xyes])
 
+# Documentation (default: no)
+AC_ARG_ENABLE([doc],AS_HELP_STRING([--enable-doc],[Enable documentation generation.]),[enable_doc=$enableval],[enable_doc="no"])
+
+AC_MSG_CHECKING(for documentation request)
+AC_MSG_RESULT($enable_doc)
+
+if test x"$enable_doc" = "xyes"
+then
+  AC_PATH_PROG([DOXYGEN], [doxygen])
+  if test x$DOXYGEN = x
+  then
+    AC_MSG_ERROR([doxygen is mandatory.])
+  else
+    WITH_DOC = 1
+  fi
+fi
+AM_CONDITIONAL(DOC_ENABLED, [test x"$enable_doc" = xyes])
+
+
 # Dependencies
 PKG_CONFIG_REQUIRES=""
 ## libusb
@@ -134,6 +153,9 @@ fi
 
 AC_SUBST(PKG_CONFIG_REQUIRES)
 
+## doxygen
+
+
 # Set C standard to C99
 # C99 standard support (default: yes)
 AC_ARG_ENABLE([std-c99],AS_HELP_STRING([--disable-std-c99],[Disable C99 standard when compiling]),[enable_std_c99=$enableval],[enable_std_c99="yes"])

src/libnfc.h

@@ -23,6 +23,7 @@
  * Provide all usefull functions (API) to handle NFC devices.
  */
 
+#ifndef _LIBNFC_H_
 #define _LIBNFC_H_
 
 #include <stdint.h>