AC_DEFUN([TORRENT_CHECK_CURL], [

  AC_CACHE_VAL(my_cv_curl_vers, [
    my_cv_curl_vers=NONE
    dnl check is the plain-text version of the required version
    check="7.12.0"
    dnl check_hex must be UPPERCASE if any hex letters are present
    check_hex="070C00"
 
    AC_MSG_CHECKING([for curl >= $check])
 
    if eval curl-config --version 2>/dev/null >/dev/null; then
      ver=`curl-config --version | sed -e "s/libcurl //g"`
      hex_ver=`curl-config --vernum | tr 'a-f' 'A-F'`
      ok=`echo "ibase=16; if($hex_ver>=$check_hex) $hex_ver else 0" | bc`
 
      if test x$ok != x0; then
        my_cv_curl_vers="$ver"
        AC_MSG_RESULT([$my_cv_curl_vers])

	CURL_CFLAGS=`curl-config --cflags`
	CURL_LIBS=`curl-config --libs`
      else
        AC_MSG_RESULT(FAILED)
        AC_MSG_ERROR([$ver is too old. Need version $check or higher.])
      fi
    else
      AC_MSG_RESULT(FAILED)
      AC_MSG_ERROR([curl-config was not found])
    fi
  ])
])


AC_DEFUN([TORRENT_CHECK_OPENSSL], [
  # first, deal with the user option : set places to be 'search' or the prefix
  AC_ARG_WITH(openssl,
    [  --with-openssl=PATH     Find the OpenSSL header and library in
                      `PATH/include' and `PATH/lib'. If PATH is of the
                      form `HEADER:LIB', then search for header files in
                      HEADER, and the library in LIB.  If you omit the
                      option completely, the configure script will
                      search for OpenSSL in a number of standard
                      places.
    ], [
      if test "$withval" = "yes"; then
	PKG_CHECK_MODULES(OPENSSL, openssl,
	                  CXXFLAGS="$CXXFLAGS `pkg-config --cflags openssl`";
                          LIBS="$LIBS -lcrypto `pkg-config --libs-only-L openssl`",
		          AC_MSG_ERROR(Could not find openssl's crypto library, try --with-openssl=PATH))

        else
	  CXXFLAGS="$CXXFLAGS -I$withval/include"
	  LIBS="$LIBS -lcrypto -L$withval/lib"
        fi
    ], [
      PKG_CHECK_MODULES(OPENSSL, openssl,
      CXXFLAGS="$CXXFLAGS `pkg-config --cflags openssl`";
      LIBS="$LIBS -lcrypto `pkg-config --libs-only-L openssl`",
      AC_MSG_ERROR(Could not find openssl's crypto library, try --with-openssl=PATH))
    ])
])


AC_DEFUN([TORRENT_MINCORE_SIGNEDNESS], [

  AC_LANG_PUSH(C++)
  AC_MSG_CHECKING(signedness of mincore parameter)

  AC_COMPILE_IFELSE(
    [[#include <sys/types.h>
      #include <sys/mman.h>
      void f() { mincore((void*)0, 0, (unsigned char*)0); }
    ]],
    [
      AC_DEFINE(USE_MINCORE_UNSIGNED, 1, use unsigned char* in mincore)
      AC_MSG_RESULT(unsigned)
    ],
    [
      AC_COMPILE_IFELSE(
        [[#include <sys/types.h>
          #include <sys/mman.h>
          void f() { mincore((void*)0, 0, (char*)0); }
        ]],
        [
          AC_DEFINE(USE_MINCORE_UNSIGNED, 0, use char* in mincore)
          AC_MSG_RESULT(signed)
        ],
        [
          AC_MSG_ERROR([mincore signedness test failed])
      ])
  ])

  AC_LANG_POP(C++)
])


AC_DEFUN([TORRENT_OTFD], [

  AC_LANG_PUSH(C++)
  AC_MSG_CHECKING(for proper overloaded template function disambiguation)

  AC_COMPILE_IFELSE(
    [[template <typename T> void f(T&) {}
      template <typename T> void f(T*) {}
      int main() { int *i = 0; f(*i); f(i); }
    ]],
    [
      AC_MSG_RESULT(yes)
    ], [
      AC_MSG_RESULT(no)
      AC_MSG_ERROR([your compiler does not properly handle overloaded template function disambiguation])
  ])

  AC_LANG_POP(C++)
])