build: new 'disable-optimization' configure option

configure.ac.in

@@ -44,6 +44,13 @@ AC_PROG_CC
 PKG_PROG_PKG_CONFIG
 AC_C_BIGENDIAN
 
+AC_ARG_ENABLE(
+	[optimization],
+	[AS_HELP_STRING([--disable-optimization],[disable compile optimization @<:@enabled@:>@])],
+	,
+	[enable_optimization="yes"]
+)
+
 AC_ARG_WITH(
 	[cygwin-native],
 	[AS_HELP_STRING([--with-cygwin-native],[compile native win32])],
@@ -51,9 +58,14 @@ AC_ARG_WITH(
 	[with_cygwin_native="no"]
 )
 
+if test "${enable_optimization}" = "no"; then
+	CFLAGS="-O0 -g"
+fi
+
 dnl Check for some target-specific stuff
 test -z "${WIN32}" && WIN32="no"
 test -z "${CYGWIN}" && CYGWIN="no"
+
 case "${host}" in
 	*-*-solaris*)
 		CPPFLAGS="${CPPFLAGS} -I/usr/local/include"