# Check for binary relocation support.
# Written by Hongli Lai
# http://autopackage.org/

AC_DEFUN([AM_BINRELOC],
[
	AC_ARG_ENABLE(binreloc,
		[  --enable-binreloc       compile with binary relocation support
                          (default=enable when available)],
		enable_binreloc=$enableval,enable_binreloc=auto)

	AC_ARG_ENABLE(binreloc-threads,
		[  --enable-binreloc-threads      compile binary relocation with threads support
	                         (default=yes)],
		enable_binreloc_threads=$enableval,enable_binreloc_threads=yes)

	BINRELOC_CFLAGS=
	BINRELOC_LIBS=
	if test "x$enable_binreloc" = "xauto"; then
		AC_CHECK_FILE([/proc/self/maps])
		AC_CACHE_CHECK([whether everything is installed to the same prefix],
			       [br_cv_valid_prefixes], [
				# datarootdir variables was introduced with autoconf-2.60
				if test "$bindir" = '${exec_prefix}/bin' -a "$sbindir" = '${exec_prefix}/sbin' -a \
					\( "$datadir" = '${prefix}/share' -o \( "$datadir" = '${datarootdir}' -a "$datarootdir" = '${prefix}/share' \) \) -a \
					"$libdir" = '${exec_prefix}/lib' -a \
					"$libexecdir" = '${exec_prefix}/libexec' -a "$sysconfdir" = '${prefix}/etc'
				then
					br_cv_valid_prefixes=yes
				else
					br_cv_valid_prefixes=no
				fi
				])
	fi
	AC_CACHE_CHECK([whether binary relocation support should be enabled],
		       [br_cv_binreloc],
		       [if test "x$enable_binreloc" = "xyes"; then
		       	       br_cv_binreloc=yes
		       elif test "x$enable_binreloc" = "xauto"; then
			       if test "x$br_cv_valid_prefixes" = "xyes" -a \
			       	       "x$ac_cv_file__proc_self_maps" = "xyes"; then
				       br_cv_binreloc=yes
			       else
				       br_cv_binreloc=no
			       fi
		       else
			       br_cv_binreloc=no
		       fi])

	if test "x$br_cv_binreloc" = "xyes"; then
		BINRELOC_CFLAGS="-DENABLE_BINRELOC"
		AC_DEFINE(ENABLE_BINRELOC,,[Use binary relocation?])
		if test "x$enable_binreloc_threads" = "xyes"; then
			AC_CHECK_LIB([pthread], [pthread_getspecific])
		fi

		AC_CACHE_CHECK([whether binary relocation should use threads],
			       [br_cv_binreloc_threads],
			       [if test "x$enable_binreloc_threads" = "xyes"; then
					if test "x$ac_cv_lib_pthread_pthread_getspecific" = "xyes"; then
						br_cv_binreloc_threads=yes
					else
						br_cv_binreloc_threads=no
					fi
			        else
					br_cv_binreloc_threads=no
				fi])

		if test "x$br_cv_binreloc_threads" = "xyes"; then
			BINRELOC_LIBS="-lpthread"
			AC_DEFINE(BR_PTHREAD,1,[Include pthread support for binary relocation?])
		else
			BINRELOC_CFLAGS="$BINRELOC_CFLAGS -DBR_PTHREADS=0"
			AC_DEFINE(BR_PTHREAD,0,[Include pthread support for binary relocation?])
		fi
	fi
	AC_SUBST(BINRELOC_CFLAGS)
	AC_SUBST(BINRELOC_LIBS)
])