Initial port to Linux (using Allegro).

64-bit fixes.
Some changes to aid portability.
A few other tweaks.

configure.ac

@@ -0,0 +1,48 @@
+# configure.ac for PCem
+#
+
+AC_PREREQ([2.61])
+AC_INIT(PCem, v9, Tom Walker <tommowalker@tommowalker.co.uk>, pcem)
+
+AM_INIT_AUTOMAKE
+AC_PROG_CC
+AC_PROG_CXX
+AM_PROG_CC_C_O
+
+
+
+AC_MSG_CHECKING([whether to enable debugging])
+AC_ARG_ENABLE(debug,
+	      AC_HELP_STRING([--enable-debug], [build debug executable]))
+if test "$enable_debug" = "yes"; then
+   CFLAGS="-Wall -O0 -g -D_DEBUG"
+   AC_MSG_RESULT([yes])
+else
+   CFLAGS="-O3"
+   AC_MSG_RESULT([no])
+fi
+
+#AC_MSG_CHECKING([for libz])
+#AX_CHECK_ZLIB
+
+AM_CONDITIONAL(OS_WIN, test "$OS" = "win")
+AM_CONDITIONAL(OS_LINUX, test "$OS" = "linux")
+
+# Do not run test for Allegro with Win32/MinGW version, as binary builds have
+# `allegro-config' missing.
+# NOTE: For the following Autoconf macro to be supported, you need to extract
+#       allegro.m4 from the DOS/Windows Allegro sources (the file is contained
+#       in `misc') and copy it to this directory or MSYS's `/share/aclocal'.
+if test "$OS" != "win"; then
+   AM_PATH_ALLEGRO(, , AC_MSG_ERROR(building B-em requires Allegro to be installed))
+fi
+
+AC_CHECK_LIB([openal], [alGetError], [], \
+	[echo "You need to install the OpenAL library."
+	 exit -1])
+AC_CHECK_LIB([alut], [alutInit], [], \
+   [echo "You need to install the ALUT library."
+    exit -1])
+
+
+AC_OUTPUT([Makefile src/Makefile])