refactor configure into separate m4 macros

this allows for some reusability with libtls

m4/check-os-options.m4

@@ -0,0 +1,77 @@
+# This must be called before AC_PROG_CC
+AC_DEFUN([CHECK_OS_OPTIONS], [
+
+CFLAGS="$CFLAGS -Wall -std=gnu99"
+
+case $host_os in
+	*aix*)
+		HOST_OS=aix
+		if test "`echo $CC | cut -d ' ' -f 1`" != "gcc" ; then
+			CFLAGS="$USER_CFLAGS"
+		fi
+		AC_SUBST([PLATFORM_LDADD], ['-lperfstat -lpthread'])
+		;;
+	*cygwin*)
+		HOST_OS=cygwin
+		;;
+	*darwin*)
+		HOST_OS=darwin
+		HOST_ABI=macosx
+		;;
+	*freebsd*)
+		HOST_OS=freebsd
+		HOST_ABI=elf
+		AC_SUBST([PROG_LDADD], ['-lthr'])
+		;;
+	*hpux*)
+		HOST_OS=hpux;
+		if test "`echo $CC | cut -d ' ' -f 1`" = "gcc" ; then
+			CFLAGS="$CFLAGS -mlp64"
+		else
+			CFLAGS="-g -O2 +DD64 $USER_CFLAGS"
+		fi
+		CPPFLAGS="$CPPFLAGS -D_XOPEN_SOURCE=600 -D__STRICT_ALIGNMENT"
+		AC_SUBST([PLATFORM_LDADD], ['-lpthread'])
+		;;
+	*linux*)
+		HOST_OS=linux
+		HOST_ABI=elf
+		CPPFLAGS="$CPPFLAGS -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_POSIX_SOURCE -D_GNU_SOURCE"
+		;;
+	*netbsd*)
+		HOST_OS=netbsd
+		CPPFLAGS="$CPPFLAGS -D_OPENBSD_SOURCE"
+		;;
+	*openbsd* | *bitrig*)
+		HOST_ABI=elf
+		AC_DEFINE([HAVE_ATTRIBUTE__BOUNDED__], [1], [OpenBSD gcc has bounded])
+		;;
+	*mingw*)
+		HOST_OS=win
+		CPPFLAGS="$CPPFLAGS -D_GNU_SOURCE -D_POSIX -D_POSIX_SOURCE -D__USE_MINGW_ANSI_STDIO"
+		CPPFLAGS="$CPPFLAGS -D_REENTRANT -D_POSIX_THREAD_SAFE_FUNCTIONS"
+		CPPFLAGS="$CPPFLAGS -DWIN32_LEAN_AND_MEAN -D_WIN32_WINNT=0x0600"
+		CPPFLAGS="$CPPFLAGS -DOPENSSL_NO_SPEED -DNO_SYSLOG"
+		CFLAGS="$CFLAGS -static-libgcc"
+		LDFLAGS="$LDFLAGS -static-libgcc"
+		AC_SUBST([PLATFORM_LDADD], ['-lws2_32'])
+		;;
+	*solaris*)
+		HOST_OS=solaris
+		HOST_ABI=elf
+		CPPFLAGS="$CPPFLAGS -D__EXTENSIONS__ -D_XOPEN_SOURCE=600 -DBSD_COMP"
+		AC_SUBST([PLATFORM_LDADD], ['-lnsl -lsocket'])
+		;;
+	*) ;;
+esac
+
+AM_CONDITIONAL([HOST_AIX],     [test x$HOST_OS = xaix])
+AM_CONDITIONAL([HOST_CYGWIN],  [test x$HOST_OS = xcygwin])
+AM_CONDITIONAL([HOST_DARWIN],  [test x$HOST_OS = xdarwin])
+AM_CONDITIONAL([HOST_FREEBSD], [test x$HOST_OS = xfreebsd])
+AM_CONDITIONAL([HOST_HPUX],    [test x$HOST_OS = xhpux])
+AM_CONDITIONAL([HOST_LINUX],   [test x$HOST_OS = xlinux])
+AM_CONDITIONAL([HOST_NETBSD],  [test x$HOST_OS = xnetbsd])
+AM_CONDITIONAL([HOST_SOLARIS], [test x$HOST_OS = xsolaris])
+AM_CONDITIONAL([HOST_WIN],     [test x$HOST_OS = xwin])
+])